Hollow Knight is a Metroidvania video game developed and published by Australian studio Team Cherry. The game was initially released for Microsoft Windows in February 2017, and later for macOS and Linux in April 2017.^[1] A port for the Nintendo Switch will also be released in early 2018. Development was partially funded through a Kickstarter crowdfunding campaign, raising over A$57,000 by the end of 2014.^[2]

The game tells the story of the game's titular Knight, on a quest to discover the secrets of the long abandoned insect kingdom of Hallownest, whose depths draw in the adventurous and the brave with the promise of treasure or the answers to ancient mysteries.

Hollow Knight's gameplay is primarily focused on exploration, platforming and combat. Players explore a large interconnected world using a variety of movement and combat techniques. In classic Metroidvania style, there are areas of the world that the player cannot access until they obtain particular items or abilities. Maps for each area must be bought from a shopkeeper generally hidden somewhere in that area, and the player can also buy upgrades that place markers on the map or allow them to reveal parts of the map as they explore. Saving the game can only be done on benches to rest on found throughout the world.

The game's combat is focused around using the Knight's nail, a weapon that resembles a sword, to strike enemies above, below, or to left and right. The nail can be upgraded to do more damage as the game progresses and can also gain special attacks by focusing energy. Many areas have a 'boss' enemy that the player must defeat in order to continue, and there are a number of sub-bosses that drop useful rewards or upgrades. Defeated enemies drop Geo, a currency that the player can use to buy items from shopkeepers. Striking enemies repeatedly also earns the player SOUL, a resource that can be used to either heal from damage or unleash special abilities such as long range spells and blasts.

If the player is killed, they respawn at the last place they rested/saved, lose all their Geo and the ability to hold the maximum amount of SOUL. They must then return to where they died and defeat their Shade in order to recover the currency and SOUL limit.

Much of the story of Hollow Knight is not told to the player directly and is instead hinted at in the environments, character interactions and secrets to discover through playing. Much of the detail is also left vague to reflect Hallownest's status as a long abandoned kingdom. The following is a summary of events that are explained through key pieces of information found throughout the game.

At the beginning, the Knight arrives in the town of Dirtmouth, a small settlement above Hallownest's ruins, with the intent to venture down to discover what lies in wait there. As they journey further through the forgotten kingdom, they encounter the possessed remnants of Hallownest's former residents and other creatures, slowly being overcome by an infection that emanates from a sealed Temple. The Knight also encounters Hornet, the self-proclaimed protector of Hallownest's ruins, who attempts to stop the Knight's quest. The Knight is eventually contacted by strange, mystical beings called the Dreamers, who implore the Knight to undo the seals they keep for some unknown purpose. As the Knight continues their quest, the history of Hallownest and the Knight itself is revealed.

Long before the kingdom's creation, a deity-like force called The Radiance aggressively ruled over bugkind, trapping them in subservience and without will. An ancient race called the Wyrms also existed during this time and one Wyrm was reborn as the Pale King, the future ruler of Hallownest, when it shed its skin outside of The Radiance's influence. The King granted sentience to the bugs and freed them from The Radiance, expanding his territory and establishing the kingdom of Hallownest. The Radiance, angered that its former thralls would soon forget it, unleashed a plague that manifested as the infection seen through the Knight's quest. The King, desperate to find a cure, began to experiment with the Void, the dark endless energy that lay in the Abyss beneath the kingdom. Using it, he hoped to construct a Vessel, an artificial entity designed without a will to be tainted by The Radiance and empty enough to contain the source of the infection inside its body. One such Vessel was deemed worthy enough and dubbed the "Hollow Knight" by the King to be the protector of Hallownest. It was sealed inside the Temple with the infection source and the Dreamers, formerly powerful beings of Hallownest civilization, chose to fall into eternal sleep in order to maintain their magical seals upon the Temple door.

However, the Pale King suddenly vanished without a trace or explanation and the Hollow Knight's body was eventually ravaged by the infection enough to begin leaking out of the Temple's depths. Without their King to aid them, Hallownest fell into ruin as its citizens were either killed or taken over by the plague. The player Knight remembers that they themselves are a failed Vessel, rejected in favor of the true Hollow Knight by the King, that was somehow able to escape the Abyss. The Dreamers, sensing the Hollow Knight's decay, reached out to the player Knight to implore them to defeat their predecessor and take up the mantle as the new Hollow Knight. Hornet, revealed to be one of the Dreamer's children, senses the player Knight's uniqueness through their battles in being able to escape the Abyss and implores it to not simply repeat history, but destroy the source of Hallownest's infection once and for all. Depending on the player's actions, Hollow Knight has three possible endings.

In the first ending, the player Knight defeats the Hollow Knight and absorbs the infection into itself to become the new Vessel. As chains manifest to hold the Knight in place, the Temple is once again resealed and the plague is held at bay. The second ending occurs if the player is able to collect a special item before fighting the Hollow Knight. Halfway through the battle, Hornet arrives to offer assistance and briefly holds the Hollow Knight at bay before she is knocked unconscious. The ending then plays out like the first, except Hornet is sealed in with the player Knight and her mask is used as the seal upon the Temple door.

The third ending occurs if the player collects the special item and uses their Dream Nail ability to enter the Hollow Knight's mind when Hornet arrives to help. Here, the player Knight can challenge The Radiance directly. After summoning the darkness of the Abyss to help, the player Knight is able to destroy The Radiance and wipe out the infection for good. As the darkness from the Temple fades, Hornet wakes to find the player Knight's shell broken and empty, implying it has sacrificed itself and returned to the Void.

Hollow Knight was revealed on Kickstarter in November 2014 and reached its initial funding goal in December of the same year. The game reached a beta state in September 2015 and continued to achieve numerous stretch goals to add in more content after an engine switch to Unity from Stencyl.^[3] Some of the stretch goal content, such as the Colosseum of Fools and The Abyss, still made it into the game despite those goals not having been attained.

In June 2017, Team Cherry partnered with IndieBox, a monthly subscription box service, to create an exclusive, physical release of the game. This limited collector’s edition included a DRM-free game disc, the official soundtrack, an instruction manual, a Steam key, and various custom-designed collectible items.^[4]

In the same month, Team Cherry announced a free update to the game entitled "Hidden Dreams", set for release on 3 August 2017. The update includes two new optional boss encounters, two new songs in the soundtrack, a new fast-travel system, and a new Stag Station to discover. The content can be accessed at any point in the game, though it is advised to wait until the late game due to the difficulty.^[5]

On 26 October 2017, Team Cherry launched the second free expansion, entitled "The Grimm Troupe". This content pack adds new major quests, new boss fights, new charms, new enemies, and other content. The update also added support for Russian, Portuguese, and Japanese.^[6]

Hollow Knight received "generally positive" reviews, according to review aggregator Metacritic.^[7]

10/10 was Jed Whitaker's score on Destructoid and said "It isn't perfect, since nothing is, but came come as close as you could get in a given genre. The new leader to beat in its sector, we're talking pure ecstasy here."^[8]

PC Gamer's Tom Marks scored the game a 92/100 with the consensus "Hollow Knight is a new classic, with a dense and detailed world full of secrets to discover."^[9]

As of November 2017, Hollow Knight has sold over 500,000 copies.^[10]

• Official website