In video games, a boss is a particularly large or challenging computer-controlled character that must be defeated at the end of a segment of a game, whether it be for a level, an episode, or the very end of the game itself (final boss). Bosses appear in many video games, particularly story or level-based first and third-person shooters, platform games, RPGs, and most shoot 'em ups. Most games feature multiple bosses, each often more difficult than the last.

Early video games followed pinball machines. Since a player can never "win" a pinball machine game, video games initially were thought of as simply "video" pinball machines. Game developers therefore included no mechanism to "win" the game. Video games were viewed simply as contest against the machine, where the only goal was to accumulate points until the machine inevitably won.

For example, early Nintendo and Atari video games such as Pong repeated the same challenge, although the speed of the object (or objects) of the game would increase. Eventually, the objects moved so fast that no player could win.

The Atari 2600 game Adventure, released in 1978, had three different dragons with differing abilities. However, it was not necessary to defeat any of them to win, and there was no level advancement in the game except by manual variation selection using the Game Select switch. In the first game variation, only the 2 slower dragons appeared. In the 2nd and 3rd variations, the 3rd and fastest dragon could be encountered. However, a player might not even encounter all of the dragons during the course of a 3rd variation game due to their random initial placement. For these reasons, the dragons are not now considered as true bosses.

The first arcade video game with a boss-like attacker was the 1979 game Galaxian. In Galaxian, waves of ships would attack the player. Each wave included a few "flagships". Destroying the flagships resulted in significant bonuses. The flagships appeared at the top of the screen, implying that they were directing the attack. The flagships were thus referred to as "bosses". Although the flagships usually were defeated by a player at the end of a level before advancing to the next level, it was not a requirement of the game.

The first arcade video game with a true boss was Phoenix introduced in 1980 by Centuri. In Phoenix, a player was first attacked with several different smaller types of enemies. After disposing of the small ships, the player is then attacked by birds. After the birds are destroyed, the player faced a large mothership. Only by defeating the large mothership could the player advance to the next level.

The first console games with a boss were Vanguard and Phoenix for the Atari 2600. Both games are ports from arcade video games. The games were released almost simultaneously. Vanguard has a part number of CX2669 while Phoenix has a part number of CX2673. If the games were released in sequence, Vanguard would have been released before Phoenix.

Template:Spoiler Many single-player games have a level structure, becoming progressively more difficult as the player advances. Bosses are a consequence of this structure, appearing at or near the end of a level and being the hardest enemies to defeat, often requiring a complex sequence of actions that the player must deduce during the battle (and, usually, multiple defeats), in order to beat them. Other games have a storyline instead of a level-based structure, but still feature bosses at various points in the story.

The 'boss battle' marks the climax of a dramatic buildup resulting from the player's anticipation and anxiousness, often including design elements such as suspenseful music that enhance this effect. For example, in Metal Gear Solid, the penultimate battle (against Metal Gear REX) has been heavily foreshadowed in dialogue, and the threat represented by the boss enhanced by an attempt to disable or destroy it before it is mobile. The final scenes in Quake 2 are tensely quiet until the player finally confronts the Makron. In Paper Mario: The Thousand-Year Door, the cutscene before the final boss shows the world being covered in darkness and also includes the final boss of the game effortlessly reducing a previous powerful boss (Sir Grodus, specifically) into a disembodied head, foreshadowing the difficulty of the battle.

A boss fest is a game with radical emphasis on boss battles. Examples of this style are Milestone's Chaos Field for Dreamcast and GameCube, Treasure's Alien Soldier for Genesis, and Taito's extremely rare Darius Alpha for the PC Engine. Shadow of the Colossus takes this one step further, as the game features no enemies except the 16 giant monsters the player must hunt down and slay. It is very rare for a game to be comprised mostly of what would normally be bosses.

Some games include a special mode, or Boss Gauntlet (sometimes called Boss Rush), in which the goal is to defeat a number of bosses one after the other. Famous games with this kind of features are the Mega Man series and Castlevania: Aria of Sorrow. Some modes challenge the player with some kind of twist, such as in Kirby: Nightmare in Dreamland and Kirby 64: The Crystal Shards, where Kirby could not use his copy powers, or Kirby Super Star mode The Arena, which consists of endurance matches against a fixed number of bosses with recovery and ability change rooms between matches. Often, modes like this are unlockables that are earned after beating the game to test a player's skill.

Bosses are traditionally used as choke-points in RPGs, used to ensure a player has taken the time to level-up (raise their abilities through fighting anonymous easier foes) before progressing to a new section of the game. A player may find that they have not increased in level sufficiently to weather a boss' attacks, and must spend time gaining experience points by fighting lowlier creatures (often a very repetitive process) before attempting the battle again. This can be viewed as an effort to ensure the player has the level the designer expects before they progress, however it is one of the more common frustrations with the genre. A well-designed RPG will have the player level up enough to defeat bosses during normal play, and may provide bonuses if they have grown strong enough to defeat certain opponents beforehand.

On the other hand, recent developments have subverted this view. With "action-RPG" games, where the player can control the character in real-time but the game system still adheres to the RPG aspects of "experience" and self-improvement through "levelling", for example in recent Castlevania games, it has become a mark of gaming skill that one can defeat a boss while at a "level" lower than an "average" player would require.

In modern MMORPGs, where the game has no true "end", the boss structure is often used within game "dungeons" or "instances". For example, in World of Warcraft, the instance Uldaman has a number of small boss encounters, many of which are skippable if the players don't want or need to do them, and a huge, highly dramatic "end boss" encounter which finishes the instance: Archaedas, the Ancient Stone Watcher.

Note that some advanced bosses may combine any number of the following basic characteristics. For example, Ugh-Zan III from Serious Sam is classified as a puzzle, giant, strong, final and unbeatable boss, and alternates between these classes like a multi-stage boss. This multiplication of characteristics has become more frequent in modern video games.

This boss is difficult to defeat because it has a lot of energy and/or deals a large amount of damage. Defeating it is generally a matter of hiding from its powerful attacks and hitting it when it's not attacking or simply wearing it down through attrition, such as Dr. Octopus and The Rhino in Spider-Man 2.

This is the simplest boss type, and may just be a regular enemy with a lot of life. A popular variant of this is that the boss will alternate between long periods of total invulnerability and short periods when a player's attacks actually weaken it. Typically, the difficulty in beating such a boss is that it will unleash devastating attacks which must be avoided during its invulnerable period by retreating or taking cover. In which case, the player must then break cover and get close to the boss during its vulnerable periods in order to counterattack, then flee again before the next cycle. As a sporting gesture, most games employing this feature offer some clue to when the boss is vulnerable to attack and when it is not, often a change in appearance (see also Puzzle Boss and Unbeatable Boss). Examples of this type include:

• Tartarus in Halo 2
• Hercules in Kingdom Hearts, who glows with 'godlike power' (as in the film) when he is invulnerable to attack.
• The Black Knight in Fire Emblem: Path of Radiance, who has near-impenatrable armor that can only be destroyed with the sacred blade Ragnell.
• Sephiroth in the Kingdom Hearts series.
• Both the Cyberdemon and Spider Mastermind in the original Doom, which are capable of dealing and absorbing much higher amounts of damage than more common foes.

This boss is difficult to defeat because it is fast and has a lot of quick attacks that are difficult to avoid. Often this kind of boss is around the same size as the player's character, and is a martial artist or similar kind. This type may have a lot of life or be relatively weak but tricky to hit. Examples of this type include:

• General Kim from True Crime: Streets of L.A. who blocks attacks rapidly and perfectly, and executes powerful Dragon Fist punches.
• In Kingdom Hearts, the final boss can kill the player with a few hits because of his rapid attacks. Others from the sequel Kingdom Hearts II are:
  • Xaldin, who is armed with 6 powerful lances using fast-paced, multi-hit wind attacks; and
  • Xemnas, the game's main antagonist and final boss, who uses a pair of lightsaber-like blades emitted from his hands along with powerful energy fields, blasts, and arcs to attack from all sides in short, but lethal strikes, demanding quick reaction times from the player.
• Jack Crowley, the final boss of Fullmetal Alchemist 2: Curse of the Crimson Elixir; he is fast, blocks efficiently, and is armed with several augmented versions of the player's attacks, as well as ones of his own.
• Shadow Link, a mini-boss from The Legend of Zelda: Ocarina of Time who is a clone of the player, mimicking his every move save that of certain weapons.
• Shiva, a mini-boss from Sega's Streets of Rage series; his repertoire of moves resembles that of the player, having the ability to perform flying kicks, throw fast flurries of attacks (complete with a knock-down "Crane Kick") and land without damage if thrown (Streets of Rage 2 only).

This type of boss is common in first- and third-person shooters. The boss is vastly larger than the player's character or any of the other bosses, often with a single relatively small weak point that must be attacked for massive damage (such as an excess eyeball, or a red bulb located on the hands or head), made difficult to hit by their sheer size, or no weak point at all (making it a puzzle boss). Examples of this type include:

• Giant Bowser in Super Princess Peach.
• Dark Mind in Kirby & the Amazing Mirror.
• Kraid in the Metroid series.
• Almost all the first stage bosses of the Mega Man X series.
• AT-AT walkers in Star Wars: Shadows of the Empire.
• The Shagohod or other Metal Gears in the Metal Gear Solid franchise.
• Tidal Wave in the Transformers PS2 game.
• Z Leo in Alien Soldier
• Mehrunes Dagon in Elder Scrolls IV: Oblivion.
• Chthon in Quake.
• GOLIATH SD/9 and Princess in TimeSplitters: Future Perfect; and
• Most of the 16 Colossi from Shadow of the Colossus.
• Metal Madness in Sonic Heroes

Some giant bosses are composed of multiple parts that must be attacked, often being interdependent. One example is the Dragon Tank from Chrono Trigger—the head heals the body and wheel, the wheel allows the tank to charge the party and the body fires lasers and missiles at the party. In-game advice suggests that the player target the head first. Other examples include:

• The nameless penultimate boss from Final Fantasy VI
• Bizarro Sephiroth from Final Fantasy VII
• The final forms of Cackletta and Princess Shroob from Mario and Luigi: Superstar Saga and Mario and Luigi: Partners in Time
• The Defense System from Tales of Symphonia.
• the King tank from Megaman and Bass.
• The Metal Gear models in the Metal Gear series

Often, if the player destroys the main part of a boss, the rest of it dies. After defeating Baigan in Final Fantasy IV, his two arms self-destruct. Such "subordinate" parts can often be revived by the boss when they are destroyed or must be destroyed before the boss can be attacked. The player must often destroy the parts to render the boss vulnerable; attack the boss until the parts are restored; and then attack the parts again, repeating the process until the boss is defeated.

These bosses are difficult to defeat because they are often hidden, either partly or completely. This can range from simply hiding behind various objects in the environment to complete invisibility. It is nearly impossible to defeat these bosses unless they are revealed in some way, usually because the arenas are too large to allow for random attacking. These may also be considered puzzle bosses, as the method for revealing them may be fairly complex.

• Ganon from The Legend of Zelda for the NES can be considered a stealth boss, as the final battle (and the only time the player directly opposes Ganon) is entirely in darkness.
• Cyborg Ninja from Metal Gear Solid qualifies as a stealth boss; once he has taken enough damage, he turns on a stealth device and becomes nearly invisible.
• The End from Metal Gear Solid 3: Snake Eater, is also a stealth boss. He is constantly hiding in the forest and he constantly tries to snipe the player. The player must snipe him back or sneak behind him. Interestingly, he can also be seen as a form of timed boss (see below), as if the player has not defeated him within one week of real time after first encountering him, this boss will die on his own.
• Demon Queen Sophia, the final boss of Maximo: Ghosts to Glory, is in a large, dark arena. She is detectable only by the occasional lightning flash or her glowing eyes.
• Omega Pirate, from Metroid Prime, is a genetically mutated space pirate who uses a cloaking device for all his fighting. He is also a giant boss.

Though these kinds of bosses usually appear in stealth games, first-person shooters and some types of RPGs, they can also be in other genres:

• In the second stage of Earthworm Jim (a run 'n gun game), Evil the Cat is a stealth boss. He hides in the background for short amounts of time and randomly leaps at the player, after which the player must quickly shoot him before he strikes.

Team bosses are different from all other forms of bosses in the sense that while most bosses are portrayed as one significant enemy, these are shown as multiple-normal or half-as-powerful-as-a-boss enemies. Team bosses are often comprised of two individuals, but they sometimes include more. Examples include:

• The Armos Knights of the Eastern Palace in The Legend of Zelda: A Link to the Past which feature a set pattern of attack before the remaining Knight attempts to trample Link.
• Team Yoshi and Team Kirby in the Super Smash Bros. series.
• The first boss of the PlayStation game Koudelka featured three spinning eyes that had to be killed independently of one another, and whilst each eye was only marginally harder to defeat than normal enemies, the trio together was sufficiently strong enough to constitute a boss.
• The Magus Sisters of Final Fantasy IV work together to form their "Delta Attack" in which Sandy casts Wall on Mindy and then Cindy casts a high level Black Magic spell on Mindy which is reflected to target a single random party member.

• Tag Team battles in which usually two opponents may leave the fight and allow the other one to attack. These are usually solved by killing both of the enemies or just hitting both of them until the health bar is drained and they both die regardless of how many hits were delivered to either of them. Examples are:
  • The zombie dogs from MediEvil; and
  • Agni and Rudra in Devil May Cry 3.
  • Kuwagast Anchus and Herculious Anchortus in Mega Man Zero 2
  • Prometheus and Pandora in Mega Man ZX.
• Some team boss encounters involve a two-part strategy, where you must fight multiple bosses individually and in their more powerful combined form. Examples of this include:
  • Bit and Byte from Mega Man X3
  • The Koopa Bros. which appear in Paper Mario.

Golden Sun and its sequel Golden Sun: The Lost Age feature a good deal of team bosses. Though many regular bosses do appear, both the first bosses and major villains of both games appear as a pair, each with considerably higher health than most other bosses up to that point. However, they can be taken down easily by focusing all or most of the player's effort on only one of the individuals.

Another type of team boss is simply a set of enemies that work together as one full boss. Reznor, the Fortress Guardian of Super Mario World, can be considered such a boss.

Many beat 'em up games with multiple players will have a boss that, when fighting against a single player, will be only one fighter—but when facing two or more heroes, will appear as multiple combatants. Examples include:

• The clones from Captain Commando
• The Mad Predator(s) from Alien vs. Predator.

A few boss battles feature a pair of contrasting enemies that the player must face simultaneously. In such battles, one of the enemies is usually very large and powerful while the other is small and quick. Examples of this include:

• Gorc and Pic from Star Wars Jedi Knight: Dark Forces II
• Tweedledum and Tweedledee from American McGee's Alice
• Logos and Ormi from Final Fantasy X-2 (although they are sometimes combined with Leblanc, you oftentimes have to fight them alone);
• Twinrova* from Legend of Zelda: Ocarina of Time; and
• Popple and Rookie from Mario & Luigi: Superstar saga

In the first two examples, the boss pairs are actually presented as twins, despite their contrasting physical differences.

Some versions of the odd couple are bosses that support each other. These are similar to team bosses that are integrated but are not as simple to defeat. Support bosses often confer special invulnerablility upon his/her partner and only with the destruction of one will the other be easily defeated. Instead of one being small and quick with the other large and strong, one will specialize in magic while the other draws on physical power. Another of this type are heavily armored defenders with very little health that depend on a fragile but efficient healer. If the healer falls, then the defender can be destroyed with little effort as he no longer has a health replenisher. On the other hand, if the defender falls, then the fragile healer will die within one or two hits. These kind of bosses depend on each other as they all have a "hit-me-on-the-head" obvious weakness that the other covers. An example would be Bowser and Kammy Koopa from Paper Mario: The Thousand-Year Door, though neither of the pair could be considered easy to beat on their own.

• Minion battles in which there will be one normal boss along with a few (2 or 3) mini-bosses or plain enemies. These are solved by either killing all of the opponents, or simply killing the "leader". Examples include:
  • Many of the bosses in Tales of Symphonia
  • In Mario & Luigi: Superstar Saga, there is a boss called Queen Bean. During battle, she spits out beans, that, if stomped on, turn into Beanie enemies. Although you can defeat them, they are eventually destroyed by Queen Bean's shockwave attack.
  • General Guy from Paper Mario
  • The Undead Core from Doukutsu Monogatari
  • Most Boss battles in Tactical RPGs.
• Army battles in which a swarm of normal enemies will come at you wave after wave after wave. The waves usually get harder as you proceed through the fight. Examples include:
  • The "Robot Carnival" and "Robot Storm" levels in Sonic Heroes
  • A level involving a swarm of robots in the Futurama console game.
  • General Guy from Paper Mario (ends with a regular boss)
  • Bikke's pirates in the original Final Fantasy
• Generator battles, where one or more tough 'factory' enemies produce large numbers of regular enemies; the player must destroy or disable the 'factory' enemies while surviving the attacks of the regular ones they create. Example of this are:
  • Icon of Sin from Doom II
  • Factories in Advance Wars 2: Black Hole Rising, which are around when versing Black Hole upon their last foothold of occupied territory within the four other continents.

A boss that is made up of several smaller enemies that have fused into one and has some or all of its components' powers, but lacks their weaknesses and may or may not resemble it's components. An example of this is the final boss in the game Mario and Luigi: Partners in Time, when the Elder Princess Shroob fused with Bowser to form Shrowser, who couldn't be attacked, and you had to dodge its attacks to beat it. Another is the Black Evil from Amazing Island, which was made up of many Evillings and was far more difficult to defeat than the evillings. Yet another example is the boss known as Digdogger in The Legend of Zelda: Oracle of Seasons, which was made of smaller enemies and had to be run over by a large spike ball via the Magnet Gloves until it split, and then the smaller enemies had to be run over or killed conventionally. The Deadhead, fought on Captain Fargos ship in Chrono Cross, is an excellent example of a combo boss.

A weaker version that appears earlier in the level is called a mini-boss, sometimes derived from the fact that it is a smaller form of another boss (alternately known as a mid-boss or sub-boss). These are generally intermediate between bosses and standard enemies in their properties. For example:

• Metal Mario from Super Smash Bros.
• Shadow Link from "The Legend of Zelda: Ocarina of Time"
• Bonkers, Mr. Frosty, Phan Phan, Bombar, Box Boxer and Crazy Hand from Kirby and the Amazing Mirror
• Nameless rogan commando from House of the Dead III

Occasionally, a defeated mini-boss or boss may return as a standard regular enemy at a later stage of the game (this is very common in RPGs as a standard enemy from later in the game makes a convinient early boss). This often stresses the use of a certain strategy or action, and the player learns how to use it well for later purposes as a result. This typically only applies to bosses or mini-bosses which are not key characters in the game's storyline. For example, in Metroid Prime, the player encounters many Baby Sheegoths before a boss battle against a fully grown one (in which special tactics are required to defeat it); upon revisiting the level at a later stage, adult Sheegoths are commonplace (however by this point of the game, the player has acquired the Plasma Beam which can hurt a Sheegoth no matter where it hits.) Other mini-bosses include Birdo, Ridley (although he gains normal boss status in later Metroid games), and Boom Boom.

Mini-bosses are also common in fighting games.

A sub-class of the Mini-Boss, normally a game who features a Grunt Boss will only have one. Grunt Bosses first appear at the beginning of the game, usually serving as the first real boss. Once they have been beaten, they will recur in numbers, but no longer as bosses. They are more or less grunts of the game, but will recur very little during the game, usually as more of a squad sergeant of masses of lesser grunts.

• The Kraken in EarthBound is a boss on the route to Scaraba, but is fought in numbers at the later Sea of Eden.
• The mafia goon with a shotgun from the second part of the first chapter of Max Payne can be considered a Grunt Boss.
• The Space Marine in Warhammer 40,000: Fire Warrior.
• The heavy unit at the end of Amazon Basin in Transformers.
• Karasuman from Castlevania: Symphony of the Night qualifies as a Grunt Boss. You fight it relatively close to the beginning to the game, and fight them as normal enemies afterwards.
• The Antlion in Final Fantasy IX.
• The Battlelord in Duke Nukem 3D.
• Sheegoths in Metroid Prime (although the normal enemy version has significantly lower HP).

A type of mini boss usually found in RPGs that, as its name implies, repeatedly chases down the main character and fights him or her at various points in the game, getting increasingly stronger each time it is encountered. For example:

• Every rival in the Pokémon series.
• Mori Ranmaru in the PS2 RPG Onimusha 3: Demon Siege
• Montross from Star Wars Bounty Hunter. The player fights him on three separate occasions throughout the game, and he gets stronger each time. He evolves from little more than a normal enemy with extra health to a powerful, heavily equipped boss that can do everything you can and more.
• Dark Samus and SA-X in the Metroid series
• The Turks from Final Fantasy VII, an organization whose members the player may fight five times total (although the last battle with them is optional, depending on which answer the player gives to their questions), the enemy being more formidable each time.
• Biggs and Wedge in Final Fantasy VIII
• Seymour Guado from Final Fantasy X
• Popple and Rookie in Mario & Luigi: Superstar Saga
• Jr. Troopa in Paper Mario
• Gilgamesh from Final Fantasy V
• Ultros from Final Fantasy VI
• Mid-Boss from Disgaea: Hour of Darkness

Stalker bosses are also common in the survival horror genre.

Stalker bosses are sometimes depicted as a troublemaker the protagonist(s) run into at a point, where the boss is beaten up, swears revenge, and returns at later points only to be defeated again. These bosses are often depicted as stubborn buffoons who sometimes becomes nice after defeating them the last time..

One final variant of a stalker boss could often be called a rival boss, or a character that has a personal vendetta against the protagonist.

Another version of the miniboss is the Super Boss (also Secret Boss), which may be fought before or after the final boss. Its existence or location may only be hinted at within the game, and usually requires the player to have already completed a certain task within the game—often involving collection of a complete set of some kind of item. This boss is usually the most difficult one in the game (even stronger than the final boss), with game designers specifically adding this unbalanced boss to challenge hardcore gamers who have leveled their characters to be strong enough to easily defeat the last boss. Defeating it usually has a reward such as a rare item or ability, although many gamers feel they would need to be at such a high level of skill as to make the reward ironically useless.[1] In recent games the items and/or weapons received for defeating an optional boss are ridiculously overpowered compared to other items and/or weapons to the point the player can generally defeat any opponent with one or two strikes. They may also be items that aren't overpowered weapons, but are needed to complete a collection of a certain type of item. Both super bosses in Super Smash Bros. Melee offer trophies, which are the collectable items of the game. Some examples of this include:

• Magician Faust from Legend Of Dragoon
• Abysson from Tales of Symphonia, whose defeat makes your formerly weak Devils Arms weapons strong enough to defeat the final boss quicker than it would normally.
• Bonetail, from Paper Mario: The Thousand Year Door, whose defeat is rewarded with the "Return Postage" badge which delivers half of the damage done on a playable character onto the enemy.
• Baal (and his later form Uber Prinny Baal), from Disgaea: Hour of Darkness, who, upon being defeated, grants Laharl the position of Tyrant which causes the Dark Assembly to approve of his bills almost all of the time. He also has an armor called the Super Robo Suit, which is the second best armor in the game and the Nemesis MK, the second best monster weapon in the game, both of which can be stolen.
• The Emerald and Ruby WEAPONS from Final Fantasy 7.
• Crazy Hand and Giga Bowser from Super Smash Bros. Melee. Crazy Hand is an unorthodox variation on the Super Boss. Instead of appearing before or after the final boss, Crazy Hand simply appears in the middle of the fight to aid the current enemy, doubling the challenge.
• Ozma from Final Fantasy IX, Ruby and Emerald Weapons in Final Fantasy VII, Ultima Weapon in Final Fantasy VIII.
• Q from Might and Magic 6: Mandate of Heaven. whose reward is a horn that shows the exact amount of hit points on any enemy in the game, but has thousands of hitpoints himself and repeatedly casts instant-death attacks.

Many games contain bosses which change shape or gain alternate attacks as they grow more heavily damaged, and can occupy several types on the list in the course of the player's battle with them. Examples of this type are present in most scrolling shoot 'em ups, where the huge vehicles presented as stage bosses would often become smaller and faster as they became more heavily damaged, or else gain new and more powerful attacks. The various stages of these bosses can normally be considered separate bosses in the various classes they occupy, since it wouldn't make any difference from the player's perspective if a new boss flew on or the old one changed shape. Almost all raid bosses in World of Warcraft or any other MMO are multi-stage bosses. This type of boss fight is common with the more powerful enemies of RPGs, such as Yunalesca from Final Fantasy X or Hojo and Sephiroth from Final Fantasy VII. Also the last bosses in the "Kingdom Hearts" series, like Ansem and Xemnas require more than five stages to defeat.

These enemies are fought before the final boss. They usually pose as a challenge, but are not as difficult as the final boss. Example of this include:

• Bass in MegaMan Battle Network 3
• Dark Meta Knight in Kirby & the Amazing Mirror
• Emperor Jillius in Klonoa: Empire of Dreams
• King Dedede in Kirby: Nightmare in Dream Land

Final boss (also last boss, end boss, or boss of the game) is the term generally used for the final antagonist of the game, such as:

• Dr. Robotnik from the Sonic the Hedgehog series. (Robotnik frequently shows up as the boss of every level, but he's often absurdly difficult to beat in his "final boss" incarnation.)
• King Dedede, Nightmare, Dark Matter, Dark Mind, etc. from the Kirby series.
• Bowser from the Super Mario Bros. series.
• Ganon from the Legend of Zelda series.
• Chaos from Final Fantasy 1.
• Mother Brain from the original Metroid.
• Ogura (Densetsu no Stafy) from the Legend of Stafy series.
• Sephiroth from Final Fantasy VII.
• Kreia from Star Wars: Knights of the Old Republic II: The Sith Lords

They are normally much larger and more powerful than any other enemies that appear in the game. This is sometimes referred to as the "last guy" derived from the common "bad guy", being the last "bad guy". There are a few common forms taken by the "last boss", including a massive creature with a small vulnerable spot and/or a creature which takes on a number of different forms during the final battle, with the ultimate form often being the most imposing.

Sometimes, the final boss requires fighting in several battles; its first form as one boss and then an evolved form as the true final boss.

There could also be multiple final bosses in one game.

Defeat of the final boss usually means the game is complete (unless there happens to be an extra "hidden boss", as explained below). Sometimes the final boss is fought before the final battle also as seen above, where the boss fights you during the normal course of the game, and shows up in a tougher form or as a tougher opponent as the final boss. Examples include

• Dr. Robotnik, as noted above
• Ugh-Zan from Serious Sam.
• Blue from Pokemon
• Dark Samus from Metroid Prime 2

These kinds of bosses don't need to be defeated. Whether you win or lose, it doesn't affect the plot. Sometimes, you do get a reward for defeating them. A good example could be the navis that you battle in the Megaman Battle Network series, such as GutsMan, KnightMan, TenguMan, TomahawkMan, ProtoMan (in some cases) and others. Another example is Culex in Super Mario RPG. One final example is the Emerald Weapon and Ruby Weapon of Final Fantasy VII fame. Typically, these bosses range from easy to harder than the final boss of the game.

• Some mini-bosses in the Kirby series can be skipped, but defeating them can give you some abilities.

Another type of boss is the puzzle boss, which is invulnerable to conventional weapons. In order to be defeated, the player must solve a puzzle—often revolving around activating some type of super weapon which is able to defeat it. Other times the player may have to activate something that drops the boss down a pit, or the boss may be defended by some impregnable shield which the player will have to somehow deactivate before they can harm the boss (sometimes the boss's shielding will eventually come back). Good examples of this kind of boss include:

• The first and final bosses from Quake
• Sophia Leigh from Tomb Raider III
• Many of the bosses from Half-Life (such as the three tentacles and the Pit Worm)
• Psychonauts
• Every single boss in Legacy of Kain: Soul Reaver
• The Sandopolis sub-boss from Sonic & Knuckles
• The final Vorticon from Commander Keen in Invasion of the Vorticons: Marooned on Mars
• Bowser in Super Mario Bros. 3 (although Bowser can be defeated with fireballs from a fire flower or with a rare Hammer Bros. suit)
• Oogie Boogie in all three Kingdom Hearts games
• The Hydra from God of War
• Most of the bosses in the Klonoa series. For example, Chipple in Klonoa: Empire of Dreams who can only be defeated by attacking his back, and Darissa from Klonoa 2: Dream Champ Tournament who can be defeated by throwing a monster at an arrow, which then rebounds to hit its underbelly.
• Smog from The Legend of Zelda: Oracle of Ages can only be damaged by moving blocks and laying down red blocks with the Cane of Somaria, which will cause the multiple Smogs to form into one large Smog.
• Gorea from Metroid Prime: Hunters.

A unique example of a puzzle boss, or possibly a trick boss, is Psycho Mantis from Metal Gear Solid. The player must figure out a way to defeat Psycho Mantis, who has the ability to "predict" the player's moves, since conventional fighting will tend to only be blocked or countered.

The Rayman series features a number of Puzzle Bosses that can only be defeated by finding their weak spot.

There is a breed of boss sometimes called the trick boss. This is a boss who is extremely powerful and can't be easily defeated by the characters at their current level. In many cases there is a particular weapon, skill, or special item that can be obtained to defeat the boss easily. Otherwise the player is left to continue to gain experience until they can beat the boss the normal way. A variant of the puzzle boss. For example, some undead characters take damage from HP healing spells, meaning an inexpensive spell or item typically used to immediately revive a character will immediately kill the boss instead (e.g. Evrae Altana from Final Fantasy X or Gi Nattak from Final Fantasy VII, both of which can be defeated easily with Phoenix Down items).

More common are elemental bosses. These tend to only take damage from their opposite 'element' in the game (dark against light, ice against fire, and so on), which the players may not be given until a certain point, until which an elemental boss will be impossible to defeat.

Another typical, classic example of the Trick Boss is Metal Man from Mega Man II, who is killed in two hits from the metal blades that can only be obtained by defeating him first (one hit if played on the North American NES version's "Normal" mode).

Another might be the optional mime boss in Final Fantasy V, who can be defeated by proving that you're a better mimic than he is. Since all he does is wait for you to act, then mimic you, the way to get him to surrender is to take no action for several minutes.

Yet another trick boss is at the end of Silent Hill. This boss automatically dies when the player runs out of ammo, so an easy way to take it down is to use up all of the character's ammo except for one bullet in one gun, then firing that last bullet during the fight.

The Armored Harriers of Paper Mario: The Thousand-Year Door are yet another example, involving the recruitment of Kid Yoshi (or whatever the player calls the Yoshi) to defeat them. Otherwise, they're invincible.

Raem's second form in Final Fantasy: Crystal Chronicles is another example, who can only be defeated using the player's memories, which become magicite for the player to use.

Poseidon in Golden Sun: The Lost Age requires you to find the pieces of and reforge the Trident of Ankohl so that you can break Poseidon's force field, which makes all other attacks useless.

The SNES game Earthbound has two trick bosses. One of them is Master Belch, whom you can disable from attacking by giving the item Jar of Fly Honey. The other is the final boss Giygas, who can only be defeated in his final form by using Paula's Pray command, which normally doesn't do any damage.

Final Fantasy VI also has a couple of Trick bosses. At the beginning of the game in the Mount Koltz section, the boss Vargas can be easily defeated by using Sabin's "Pummel" blitz. Similarly, SrBehemoth can be defeated simply by casting "Life" or using a Phoenix Down on him, since he's undead.

Krauser in Resident Evil 4: Although he is possible to beat with any of the weapons, most players would take a lot of damage and use a lot of ammo making the rest of the game harder. His weakness is to the knife, which does about 40 times more damage then it would any other time, killing him in only a few slashes.

The Naughty Sorceress in the online game Kingdom of Loathing is a trick boss, because her power is dependent upon the player's own statistics. Also, the player must have a seemingly useless special weapon equipped to win the battle; if the weapon is not equipped, even if the Sorceress is defeated in battle, the player will still ultimately lose.

Supreme Executive Chairman Drek, the final boss in Ratchet & Clank is also more or less a trick boss. Depleting your conventional arsenal in his direction does not make a significant dent in his armor. By replaying other parts of the game (say, to discover the remaining secret areas) and saving up enough Bolts (money) to buy the RYNO, Drek can be defeated easily.

Occasionally the boss fight's length is determined not by the player's actions, but by a countdown of some sort. In such cases, the boss itself is generally impossible to destroy; the player must wait until the time limit expires and survive the boss' attacks until then. An early example was in Sonic CD, where Eggman would drop bombs while moving the player towards spikes with a conveyor belt. Eventually the mech would break due to friction from the belt. Variations include:

• An invincible boss chasing the player to a certain point (as with the Shagohod chase in Metal Gear Solid 3: Snake Eater, where the boss cannot be destroyed while chasing the player on the runway);
• A boss which the player must hold off while a timed explosive or other character defeats it (as with Llednar Twem in Final Fantasy Tactics Advance); and
• A multi-stage boss where one stage is determined by time limit rather than damage (as with the Morphing Bydo boss' first form in R-Type III: The Third Lightning).
• An fight where, although the boss in not defeated, the player must survive for a certain amount of time to continue (as is the case in many fights during the story mode of Dragon Ball Z: Budokai Tenkai'chi).

The opposite form also exists; in this type, rather than the boss being defeated after a time limit expires, the player must defeat the boss within the time limit; they will generally otherwise be killed or inconvenienced in some way when the time runs out. Reasons for the time limit vary. Typical cases include: a bomb with a countdown that will kill the player after a given length of time; the boss calling for unbeatable reinforcements that will arrive when the time runs out; another character being in peril and requiring the player to defeat the boss to render aid to them; or the boss building up a devastating attack it will unleash when the time runs out. A typical example is the final boss of Revenge of Shinobi.

Metal Gear Solid 3: Snake Eater timed bosses are The Joy (more commonly referred to as The Boss), which ends after 10 minutes, with jet fighters bombing you, the boss and the entire fight location, and Colonel Volgin in which you have an unidentified (but short) time before the C3 bombs that Naked Snake (the protagonist) himself set before the fight blow up the whole area. Subsequently, the Resident Evil series has employed these types of bosses as their final bosses.

In Metal Gear Solid, the two encounters with Liquid Snake shift between different types of Timed Boss fights. First, you must defeat him in a bare-fisted fight before a timed explosion goes off. In the final confrontation, you must survive for a set distance in an armed jeep race.

A unique example is found in R-Type Final as well as Ikaruga, where every boss has a time limit as well as a damage limit. In this instance, bosses will either explode on their own, destroy the player's ship or disappear once the time limit expires, thus allowing a player to defeat them simply by evading their attacks.

An interesting spin on this type of boss is where, in some situations, the game may give a special reward for dealing a certain amount of damage to the boss in a given time limit. An example of this is the X-ATM-092 from Final Fantasy VIII, which chases your party through the town attempting to intercept the party. Once this boss is knocked down, you have the option of running or trying to reach its maximum damage limit before it gets back up again. Choosing the latter will result in a handy reward.

A recent, unique version of the Timed Boss is the Luxord boss fight from Kingdom Hearts II. The boss has no hit points as per the custom of the game, but instead has a time bar, as does Sora. The point of the battle is to drain the boss' time bar faster than Sora's is drained. Both time bars drain at the same speed, but doing damage to the boss can cause his bar to drain faster.

The reverse case (where the player must beat the boss before the time runs out), the boss not only has the in-game advantage, but the psychological advantage as well. The player will tend to get desperate during the few remaining seconds when fighting a boss and will tend to make mistakes as a result.

An example of this is the final battle with Dr. Weil in Mega Man Zero 4. In this final battle, the player only has two minutes to defeat him before the space station being fought on collides into the earth.

Related to the trick boss is the "unbeatable boss" or "scripted battle", often found in RPGs. This rare boss is actually undefeatable—either invincible or massively more powerful than the player—and for storyline purposes, the player must lose. This however does not result in a game over. Alternatively, the player may have to find a way to escape before the boss kills them, or survive for a set period of time by evading or defending against the boss. Often, the unbeatable boss will become defeatable much later in the game, either: when the player has significantly grown in power (as with Saturos and Menardi in Golden Sun); or obtained a certain ability/weapon/item; or when some story element has removed the boss' invincibility. Some multi-stage bosses start as an unbeatable boss. After defeating the player in the first phase, something happens to remove their invincibility, and they become beatable in the next phase.

Another unbeatable boss is Vile from Mega Man X. Vile is encountered at the end of the first level of the game. He cannot die, and he will be able to subdue you in only a few hits. Vile is later encountered at the end of the game, when X and Zero team up to destroy him.

Doopliss from Paper Mario: The Thousand Year Door steals Mario's identity and every time Mario passes a certain shed, Doopliss will appear and battle you. Doopliss is undefeatable during this portion (this is explained in game as an ability Doopliss possesses that grants him extraordinary power as long as no one can guess his name), although he can be defeated at the end of the chapter. The Shadow Queen, the final boss of the same game, can't be defeated in her first form, and she uses her undead hands to absorb the audience, restoring her health. However, she is weakened and becomes vulnerable after a few turns and is (relatively) easily defeated with the right items and experience points.

In Castlevania: Curse of Darkness, Hector is challenged by Trevor Belmont about 1/5 through the game in the Garibaldi Temple. At this point, he seems unbeatable (Being Level 40 whereas the average player is level 15) until you take off 1/8 of his health, which triggers a cutscene with Trevor taunting Hector at how weak he is. Trevor is then fought again near the end of the game, bearing the same levels and attacks as before whereas Hector's own level is much higher. At that point, Trevor must be defeated to advance the game.

In Final Fantasy X, Tidus is attacked by an underwater enemy called Geosganeo upon first arriving in the main game world of Spira. The boss uses only one physical attack, which damages Tidus for half his current health, meaning he can never die—if he is reduced to 1 HP, the game rounds the damage of 0.5 HP down to 0. Geosganeo can be defeated much later on after the airship is acquired, and at this stage, he is capable of killing party members with attacks that stone or KO instantly, though he only poses a challenge to lower-leveled parties.

In The Legend of Dragoon, the player will fight gladiator style against increasingly harder (yet still beatable) enemies to progress to the next round. Even if you lose, the referee of that match will disqualify the 'winner' (i.e. the computer) for cheating until you face Lloyd, who is unbeatable. Losing to him goes to a cutscene where he is the winner of the tournament (much later in the game, Lloyd is revealed to be of a different race, explaining why he's much stronger than all the other competitors).

In Kingdom Hearts', Leon is also an example. Even if you beat him (which is a hard task at that point in the game), the story makes it so that Sora collapses from fatigue in battle, losing to Leon.

Chrono Trigger has an end boss named Lavos, who is encountered in one supposedly-impossible encounter midway through the game. It is possible (especially with the New Game+ option gained on beating the game once) to defeat him at that point; doing so actually ends the game in an easter-egg victory. A lesser "unbeatable" boss is the Golem sent to capture the party. Even when this boss is defeated, the party is inexplicably captured.

At the beginning of Super Metroid, Samus must fight against Ridley, whom cannot be defeated. In the second encounter later in the game, he can be killed.

Another example from the Metroid series is the SA-X from Metroid Fusion. The SA-X carries all the equipment Samus finished Super Metroid with and can kill Samus easily. The player must wait until the final portion of the game, when they are strong enough to face it in a one-on-one duel.

Baldur's Gate II: Throne of Bhaal features a Fire Giant Bhaalspawn called Yaga-Shura. Yaga-Shura is invincible because his heart had been removed with a spell cast upon it. After a lengthy quest of retrieving it, and undoing the spell, Yaga-Shura can finally be felled.

In Deus Ex, JC Denton will at one point be captured by UNATCO agent Gunther Hermann. The player can either surrender to Gunther or fight him; however, resisting is useless since at this point in the game, Gunther is invincible. Gunther can eventually be killed later in the game (possibly without even having a battle).

This type of boss is not really an enemy or an antagonist. It is just a character that you must challenge in a sport or activity. A good example is a boss that you must simply race or beat in a game. Even some bosses like Koopa the Quick from Super Mario 64 aren't enemies, but are friends that you must help to fix something. Even though Non-Antagonist bosses aren't enemies, in a lot of cases, they might still inflict damage on you if you touch them. Examples are:

• Justy from Pokémon Colosseum and Pokémon XD: Gale of Darkness;
• In the Sonic series, Sonic battles Shadow the Hedgehog and Knuckles the Echidna as an enemy at first, but become strong rivals afterwards. They never kill each other, but they do inflict damage to each other.

Another type of this is a character who appears to be a villian but then reveals eather at the time of their defeat or later on that they were helpping the hero learn a lession or a new skill they could not defeat the real villian without.Yet another type is a hero who is being controled in some way by evil forces.

Sometimes a game will hype up one of its antagonists, implying that the player will be forced to face the villain as a major boss at some point in the game. When the moment arrives, though, the boss battle is either interrupted or surprisingly easy. This is sometimes due to the preceding level being incredibly difficult (after which a simple boss battle is a welcome surprise), or it is sometimes used as a means to introduce a more powerful, more threatening antagonist (after which a different boss battle, or even a new game may follow. see: cliffhanger).

The best example of this is Bob the Killer Goldfish, who appears as a non-boss in both Earthworm Jim and Earthworm Jim 2. Though there is little if any fighting between the game character and Bob, his entertaining parody of a boss battle sequence has made him a memorable villain.

Another example of this is the "Launch Base Zone" appearance of Knuckles the Echidna in Sonic the Hedgehog 3. Despite making problems for Sonic and Tails from the very beginning of the game, Knuckles' confrontation with the hedgehog is interrupted after the first punch, as Dr. Robotnik launches the Second Death Egg and intiates the actual boss battle.

This also happens in:

• Final Fantasy VI, when the party encounters Emperor Gestahl on the Floating Continent.
• Star Fox Adventures, in the fight against General Scales.
• The grocery store-staged 'final showdown' with a pumped-up Mysterio in Spider-Man 2 ...who requires one punch to defeat.
• Gunstar Heroes, during the fifth level. An odd-looking soldier appears at the end of the level, and the description text calls him "Final Great Soldier", with the only listed attack being "Love Love Dancing". Before he can do anything, Smash Daisaku (one of the game's main antagonists) appears and tosses him away, then fights the player.
• Castlevania: Aria of Sorrow, Soma enters a boss room where a swarm of bats gather and form the most classic of Castlevania bosses, The Phantom Bat. However, just as the fight is about to begin he is suddenly crushed by Balore, the real boss.

Another example comes from Paper Mario, where in the final castle, a door claims that he will only let Mario pass if he can defeat the Koopa Bros. (who Mario defeated earlier) but they claim they have learned a new, impossibly powerful move. But before the battle begins, the stalker boss, Jr. Troopa, barges in, knocks out the Koopa Bros., and fights Mario instead. The door allows Mario entry after this battle on the grounds that since Jr. Troopa beat the Koopa Bros. and Mario beat Jr. Troopa, Mario indirectly beat the Koopa Bros.

In complex games (particularly role-playing games), bosses are so noted for effective attacks and a large number of hit points. They also have "special" attacks, such as stunning/freezing the player, teleportation, inflicting massive damage onto the characters, inflicting curses on the characters that decrease their abilities, and so forth. Bosses are often immune to certain abilities that the player possesses, and often can only be defeated by specific attacks and strategies, or by using the environment or their own attacks against them. A common way of implying this power is to make the boss much larger than the player's on-screen representation, as opposed to normal enemies, who are more commonly smaller than the player, or at most roughly equal in size. Some bosses have multiple targets, the targets being either its allies (like a boss fight with one or two bodyguards) or multiple parts of its body. The battle with this breed ends whenever the main target or all of its parts die, but sometimes the pieces will be revived if the player does not kill them quick enough. In some games in which combat takes place in real-time (like in The Legend of Zelda or MMORPGs), some bosses may use the environment to their advantage. This includes the boss picking up objects and throwing them at the player characters, lighting the stage on fire, dropping mine-like explosives, or by reducing the available space to fight in. Sometimes the player can use the environment to their advantage too, like standing in a specific space to avoid damage from an attack or knocking projectiles back at the boss and stunning him/her/it. Sometimes it is a certain object in the area that can damage the boss. This is attributed to the "Puzzle Boss."

In fighting games such as Mortal Kombat, the final few characters the player faces in matches are usually referred to as bosses, as they are placed at the end of the game and often have noticeably greater difficulty than previous opponents. Bosses in these games are often not available as playable characters at leisure, or may have a much weaker version available for play. Bosses are also sometimes characterised by being difficult, or completely unrelated, to the rest of other fighter's templates owing to a strange size, shape or types of attacks, as well has having more priority and dealing much more damage. Example include Asmodeus of Mace: The Dark Age, Onslaught from Marvel vs. Capcom: Clash of Super Heroes, and Master Hand of the Super Smash Brothers series, are is completely different to any other opponents not only by size, but the way the fight decisions are conducted.

In scrolling fighting games and other arcade games, a boss's health level is often determined by a health bar comparatively longer than the player's, sometimes taking up several lifebar lengths, or as in the Mega Man Zero series, where the color of the lifebar shows how many of them he has and the boss often has a bar which is two colors over Zero himself. When not determined in this manner, the character may also flash red as he takes hits, progressively flashing faster until he is defeated. This not only determines the boss's health, but also permits internal programming to discreetly adjust it as players enter and leave the game during the boss battle. Sometimes, bosses may also adjust their attacks (including desperation moves when near defeat) according to how much damage they are taking.

In more fantasy- or science fiction-oriented First Person Shooter games like Doom or Half-Life where the player faces different species of monsters, bosses are generally large, highly durable monsters, often with their own unique weapons or special pre-scripted attacks and complex arenas. In more realistic FPS games where the player faces exclusively human foes, such as Wolfenstein 3D, bosses often are unique characters who behave exactly like regular enemies, only with better weapons, more health, and typically greater intelligence; or else they are vehicles such as tanks or attack helicopters to account for their greater durability and damage. Some FPS bosses have weak points that are the only damagable point such as for these games, House of the Dead, Time Crisis and Virtua Cop.

Scrolling shooters almost always feature end-of-stage bosses, which are often screen-filling vehicles or creatures with multiple attack phases depending on how much damage they have taken; frequently they change shape to mark these phases. Mechanical bosses are often freakishly oversized, such as the Ground Battleship in Strikers 1945. Some scrolling shooters will also have a Boss Stage, a stage in the game that is made almost entirely of one gigantic ship several screens long/wide, as well as any escorts. The player(s) usually have to destroy the ship piece by piece, often causing sections to fall off. However, these stages tend to end in a traditional boss, generally the ship's engine or command section. The R-Type series is known for having one of the earliest examples of this kind of stage. There are also sometimes levels made entirely of boss fights, which are given varied nicknames such as Boss Alleys or the Boss Parade. The Gradius series (since the second installment) are known for featuring this kind of stage. Its spin-off series Parodius feature the Stage of Moai in every installment.

While almost nonexistent in realistic flight sims, boss encounters do appear in those the focus more on action, such as the Ace Combat games. This will either take the form of an enemy 'ace' or group of aces significantly more difficult to hit and exponentially more skilled than the standard enemies (ADFX-02 and other aces from Ace Combat Zero, UI-4054 from Ace Combat 3, or a squadron of X-02 Wyverns from Ace Combat 5: Operation Katina), or sometimes a massive vehicle such as the Arkbird enemy in Ace Combat 5, a spaceplane as big as an aircraft carrier. Other 'boss' like encounters can be stages that require extremely precise flying, often down narrow tunnels; The Megalith stage from Ace Combat 04 fits this description well.

Unlike conventional flight sims, space sims often contain bosses, usually in the form of colossal, heavily armoured capital ships which dwarf the small ships piloted by players and conventional enemies (almost invariably one-man fighter or bomber spacecraft). Descent: FreeSpace and its sequel FreeSpace 2 are excellent examples, frequently relying on boss levels in the form of missions where squadrons of small craft must engage and either destroy or capture vast enemy vessels. Conversely, sometimes in such games the roles are reversed, for example when an allied capital "boss" ship must be defended against swarms of regular enemies. Occasionally, two capital ships engaging each other in a boss fight actually form nothing more than a backdrop to a conventional dogfight.

In rhythm and dance games, such as Dance Dance Revolution or Pump It Up, the hardest songs are usually considered "Bosses", due to their extreme difficulty and speed (or lack thereof, in some cases). In Dance Dance Revolution in particular, many of the games have Extra Stages which feature the hardest songs plus several modifications to make the songs more difficult, such as scrolling from top-to-bottom instead of the usual bottom-to-top.

Bosses have recently fallen out of favor with some videogamers and specific game designers; it is argued by them that they are a hangover from pay-to-play arcade games, and inappropriate for current games. Poorly engineered bosses may simply be an enemy which absorbs or deals an exasperating amount of damage without providing especially engaging gameplay, existing purely to slow the player's progress. Particularly boss-heavy games may lack coherent segments between the bosses; this is frequently an issue in 2D shooters such as Gunstar Heroes and is apparent in the PS2 puzzle game Shadow of the Colossus.

Some gamers have complained that bosses can break the suspension of disbelief by disrupting the level of realism. In games which attempt for a "realistic" atmosphere where the player character and the enemies can survive about as much damage as a "real" human being (albeit perhaps one wearing body armor) could, it can be quite jarring to suddenly encounter an enemy who can survive superhuman amounts of damage, especially when this enemy is apparently human - this is particularly noticeable, for example, in Max Payne. Developers have tried to justify these occurrences by various (sometimes far-fetched) means, like providing the player's opponent with extremely advanced body armor (such as the final boss in the otherwise (gruesomely) realistic Soldier of Fortune). An interesting justification for a human character's extreme resistance to damage (or, more likely, the pain it causes) is found in Hitman: Codename 47, where a "boss" character snorts a preposterous amount of cocaine before engaging the player in a gunfight (although otherwise, in the Hitman series, all targets the player must assassinate are as human as the player himself, and even that boss can be killed easily if the player can find a way to kill him before he snorts the cocaine).

Also, the incongruously drawn-out boss battles in Red Faction 2 and other similar games were derided by many as repetitive, awkward endings to otherwise dramatic, coherent games. However, the frequent lock-in battles of some games which claim to be without bosses are often just as problematic for suspension of disbelief, since they require the player to accept that, for example, a character with a rocket launcher could not destroy a flimsy door barring his escape. Some games attempt to overcome this by using energy-based barriers in place of physical obstructions.

Alternatively, some view bosses as the ultimate expression of the concepts in the game's design, the other segments bridging and introducing ideas to be explored fully in the boss battles. Developer Treasure constructed Alien Soldier as a relentless series of bosses to interesting effect; the Metal Gear series includes its bosses as the ongoing storyline, battles with them driving the plot ahead; in the Metroid saga, bosses test the player's skill and grant them new abilities that allow the gameplay to expand.

Games may instead have various scenarios which serve as boss "replacements," however, such as requiring the player to defeat a larger-than-normal amount of (often strong) enemies in a limited period of time or a confined space with little cover. This kind of 'boss room' is especially common in first person shooting games, with its origins in the Doom series. A common version is to force the player to remain in one location while waves of enemies attack them; the player being forced to fight them all to progress either because they are locked in (a frequent occurrence in Black, where such a situation occurs at least once on most levels, and the Serious Sam games which consist of little else) or because there is something in the area they must protect for a fixed period of time (possibly the most well-known example being the infamous sequence in GoldenEye 007 where the player must guard Natalya; the Pegasus Bridge and Pavlov's House sequences in Call of Duty are other examples). In World 4-1 of Super Mario Bros. 2, there is no boss. Rather, the boss music plays and Mario/Luigi/Peach/Toad must go through a room with a large number of Autobombs.

It is also worth noting that the line claimed to exist between these "replacement" scenarios and a true boss is not a clear one, and many consider these situations just as much boss encounters as any other type; as an example, the final boss of Serious Sam: the Second Encounter, Mordekai the Summoner, has no means of directly attacking the player and can only summon other enemies. He is thus effectively an object the player must destroy to end a "boss room"-type battle, much as some such battles would end when the player destroys a bunker or computer in the room. Certain games combine the "puzzle" and "army" boss variants to form a situation reminiscent of a boss fight, attempting to perform a complicated sequence of actions while under assault from endless waves of enemies, without technically having a boss present. Finally, Shadow of the Colossus takes the convention of bosses in a whole different direction: in the case of the Collossi, the bosses are the levels.

• List of video game bosses

• The Ten Best Boss Fights – according to GameSpot.com
• General-purpose Boss Fighting Guide
• Who's the Boss? from Wired News
• Boss battles – article discussing good boss design
• Ban The Boss – article criticising the boss concept