[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 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.

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.

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.

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.

[5] Renata Price of Vice News wrote that the game's atmosphere evoked the "systemic death spiral at the heart of capitalism".

"[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.