The film adaptation of the indie game "Iron Lung" garnered $21.5 million during its opening weekend.

An indie horror movie inspired by the game Iron Lung gathered $21.5 million during its first weekend in theaters. This notable performance, attributed to YouTuber Mark Fischbach, known online as Markiplier, underscores the promise of video game adaptations, even those with modest budgets. The movie was created with an investment of $3 million.

Iron Lung, which draws its narrative from the 2022 video game by the same title, was penned, helmed, and featured Fischbach, who had previously introduced the game to his 38.2 million YouTube followers. Although it had a selective global release, the movie made $17.8 million from its U.S. screenings, landing in the second spot on domestic charts, following Sam Raimi's horror feature, Send Help.

The storyline parallels that of the game, centering on a decaying submarine's pilot journeying through a blood ocean on a remote moon after humanity's decline. Developed by David Szymanski, the game debuted on Steam in 2022 and achieved approximately 310,000 sales. It later became available on Switch and PS5.

Fischbach, a supporter of the game from the early days, embarked on the filmmaking process in 2023, concluding the shoot in 2024.

Despite its success, the movie's earnings were dwarfed by the Five Nights At Freddy's film, which grossed $80 million on its opening weekend. However, Iron Lung had a significantly lower financial outlay, while Five Nights At Freddy's already boasted a wider audience, with millions of game sales.

Several other indie game adaptations are under development, including Dredge and Poppy Playtime. Mob Entertainment's George Krstic commented positively on collaborating with Legendary on Poppy Playtime, highlighting their deep understanding and care for the intellectual property.