Iron Lung
Developer(s)	David Szymanski
Publisher(s)	David Szymanski (Windows) Dread XP (Switch)
Engine	Unity
Platform(s)	Windows, Nintendo Switch
Release	Windows March 10, 2022 Switch December 19, 2022
Mode(s)	Single-player

Iron Lung is a 2022 first-person submarine simulation horror game developed and published by David Szymanski.^[1] The player controls an unnamed convict who explores an ocean of blood on a desolate moon in a small, rusty submarine nicknamed the "Iron Lung". The game was released for Windows on March 10, 2022. A Nintendo Switch port was released on December 19, 2022.^[2]

The player controls a silent protagonist that pilots a midget submarine. Gameplay is set entirely within the one-room submarine, with little room to move. The submarine is controlled using its navigational equipment at the front. The submarine's heading and position are displayed with a minimalist interface. The submarine lacks any viewing ports, and the player cannot exit it, forcing them to use their map and the submarine's camera to navigate the game map. At certain points, the player must use the submarine camera to capture photographs, which reveal surroundings and details about the area the player is in. Events occur throughout the game, including scripted decreases in oxygen and pressure which do not affect gameplay.^[3]

The game also includes optional cheat codes that affect the visuals, such as a "rave mode" with colorful lights and a "Markiplier mode" that replaces most textures with the face of Markiplier.^[4]

In a future where humanity has colonized space, an event known as "The Quiet Rapture" causes all stars and habitable planets in the universe to inexplicably disappear, leaving only individuals aboard space stations or starships alive. To secure the survival of humanity, the Consolidation of Iron (COI) launches an expedition to AT-5, a desolate moon that has recently formed an expansive ocean of human blood, believed to hold vital resources desperately required to sustain human life. The player character is a convict sent to navigate the trenches of the blood ocean in a small submarine known officially as SM-13, nicknamed the "Iron Lung", to verify the existence of the resources. Due to the pressure and depth of the ocean, the main hatch is welded shut, the forward viewport has been encased in metal, and communications are lost shortly after submerging. The player is promised freedom upon their return to the surface, but a note left by a previous occupant of the submarine warns them otherwise.

The player takes control of the Iron Lung as they navigate through the treacherous, narrow caves and trenches. Using the submarine's camera, they capture photographs of points of interest scattered around the map. However, the photographs reveal increasingly unusual features such as plant growth, rock formations which defy explanation, large unidentified skeletons, and artificial structures resembling building facades. The player must also contend with a fire which breaks out in the rear of the submarine. As the Iron Lung draws closer to one point of interest, an orb of light, the vessel begins to shake violently. At another point, the player captures the eye of a large, unidentified sea creature, which then attacks the Iron Lung in retaliation, causing a significant leak. After reaching the final point of interest, as the player attempts to reach the camera controls, the creature breaches the submarine, ending the game and returning the player to the title screen.

A post-game text entry reveals that there is no current method of retrieving the remains or photographs from the destroyed submarine, so the player's mission was in vain. Despite this, the text remains optimistic, asserting that humanity will find a solution to the Quiet Rapture somewhere in the universe.

Iron Lung received generally positive reviews, with reviewer Aaron Boehm of Bloody Disgusting praising the game's "oppressive" atmosphere and "exceptional sound design".^[5] Renata Price of Vice News wrote that the game's atmosphere evoked the "systemic death spiral at the heart of capitalism".^[3] Zoey Handley of Destructoid praised the game's horror concept, arguing it could only be fully realized in an "interactive medium" like video gaming.^[6]

In December 2023, Szymanski faced criticism online for increasing the price of the game by two dollars, and sales of the game dropped after the price adjustment.^[7]

In June 2023, following the implosion of the Titan submersible, Iron Lung experienced a surge in popularity and sales, with some comparing aspects of the video game with the real-world circumstances of the five victims onboard Titan, such as the inability to open the submersible from the inside. Szymanski expressed his discomfort at the increased sales in multiple tweets, first posting a weekly sales chart from Steam with the words "This feels so wrong"^[8][9] and further remarking that the thought of Titan's occupants being trapped in a similar scenario was "pretty horrific, even if it was their own bad decisions."^[10]

On April 21, 2023, American YouTuber Mark Fischbach, known online as Markiplier, announced he would be adapting Iron Lung into a horror film.^{[11][12][13][14]} Fischbach, who had previously played Iron Lung on his channel,^[13] announced the film would be self-financed, star himself alongside co-star Caroline Rose Kaplan, and use his own script.^[11][14] David Szymanski has also confirmed that he has been involved with the film since pre-production, assisting with its screenplay and being on set during filming, and that he is set to have a small cameo in the film.^[15] The Iron Lung film is set to be the first theatrical film directed and produced by Fischbach, who will co-produce it alongside Will Hyde and Jeff Guerrero.^[14] A teaser trailer was released alongside the announcement,^[16] and an official trailer was later uploaded to Fischbach's YouTube channel on October 14, 2023.^[17]

• Dusk (video game)
• List of underwater science fiction works