Iron Lung is a 2026 American science fictionhorror film written and directed by Mark Fischbach, credited under his online alias Markiplier, in his feature directorial debut. It is based on the 2022 video game by David Szymanski. The film stars Fischbach, Caroline Rose Kaplan, Troy Baker, Elsie Lovelock, Elle LaMont, Seán McLoughlin, and Isaac McKee. The plot follows a convict named Simon (Fischbach) who is forced to pilot a submarine through a desolate moon's ocean of blood, after an event known as the Quiet Rapture caused the majority of humanity and all stars to disappear without warning.
Development on a Iron Lung film adaptation began in April 2023, when Fischbach announced he would be adapting the game. Iron Lung was released in North America on January 30, 2026, to mixed reviews from critics. It was a financial success, grossing $21 million against a production budget of $3 million.
Plot
In a distant future, an event called the Quiet Rapture severs all contact with colonized planets. All star systems and planets vanish, leaving only those on space stations or ships alive; the human population is reduced to very few.
Simon is imprisoned for his involvement in the destruction of a space station, Filament Station. His punishment is testing and piloting the SM-13 submarine, nicknamed the "Iron Lung." Simon is told that if he completes his mission of exploring an ocean of blood on a moon named AT-5, he will be freed. The sub is welded shut and its porthole is sealed, meaning Simon can only see outside with a crude camera. Limited communications arrive through a radio from one of the crew members who is present at the surface.
During the dive, the submarine's sensors indicate movement outside. Simon captures images of a skeleton on the ocean floor. Officials return him to the surface to review his findings. They choose to send Simon back down to collect a sample from the skeleton. A frustrated Simon, demanding to be freed, activates the camera in a fit of rage and captures an image of the station's crew and commander. Curiously, the display shows human skeletons: the "camera" is actually an X-ray imaging device which heavily irradiates the crew.
Sent back into the blood ocean, Simon discovers audio logs from another pilot, proving he was lied to by the officials about being the first. He tries to tell the crew commander about an image of a living creature he took, but she urges him to collect the sample. As Simon progresses, blood and an unidentified liquid drip into the sub. Simon is knocked unconscious when he collects a sample. He awakes in the sub with camera pictures showing movement. He repairs the sub and attempts to return to a charted area, all the while hallucinating and losing touch with reality.
Simon encounters a wrecked submarine labeled SM-8 but is unable to access the data within its black box. A woman talks to him through the radio about a godly light beneath the ocean, and Simon believes he is hallucinating. In a vision where the sub is destroyed, Simon breaks the surface to see a giant eye filling a stormy red sky. Simon awakes again. The crew commander says he has been missing for several days, far longer than his oxygen supply should have lasted. She tells him to recover SM-8's data, promising to rescue him herself if he complies, as well as also revealing her name to be Ava. Meanwhile, blood and congealed organic matter collect inside the sub. Contact with the blood, along with radiation emitted by the camera, causes abnormalities on Simon's skin.
Simon reaches SM-8 and accesses its data, including audio logs confirming that the blood ocean comprises human blood. As the sub fills with more blood and fleshy matter, Simon learns Ava cannot rescue him. She apologizes and asks him to protect the SM-8 data because it may save what is left of humanity. Simultaneously, the mysterious woman's voice tells Simon to destroy the data so others will not learn about the light. Shortly after, a creature destroys Ava's vessel. Simon, struggling to move through the blood and fleshy material growing in the sub and on his body, ties the black box to a life vest. He sabotages the Iron Lung so that its hull will fail under pressure. The sub implodes upon being bitten by the creature, killing it and Simon. The life vest is shown floating on the surface of the blood ocean, with its water-activated light on and the black box still intact.
Mark Fischbach directed, edited, wrote, starred in, and funded Iron Lung.
On February 16, 2023, David Szymanski joked on Twitter that Mark Fischbach and Seán McLoughlin (known by their online usernames Markiplier and Jacksepticeye, respectively) would be starring in a film adaptation of the game Iron Lung which Fischbach and McLoughlin both played, with a soundtrack by Andrew Hulshult, slated for a summer release.[9][10] In an interview with Variety on March 8, 2023, Fischbach confirmed he was directing, writing, and acting for a film, but did not state what it was.[11] On May 7, 2023, McLoughlin confirmed on Twitter that he would be in it.[12][bettersourceneeded] Szymanski assisted with the script and pre-production, and filmed a brief cameo for the film.[10] Andrew Hulshult was also confirmed to be scoring.[13]Iron Lung is the first film soundtrack that Hulshult worked on.[14]
Filming
On April 21, 2023, Fischbach officially announced a film adaptation of Iron Lung with the release of a teaser trailer.[15][16][17] Additionally, Deadline Hollywood reported that Fischbach was also self-financing, co-starring with Caroline Rose Kaplan, and producing with Will Hyde and Jeff Guerrero; filming had already commenced in Austin, Texas.[18] Szymanski confirmed it was intended for a theatrical release,[19] marking it Fischbach's first theatrical film; he previously directed and wrote the YouTube Original interactive films A Heist with Markiplier (2019) and In Space with Markiplier (2022).[18]
Fischbach's makeup designer Anna Fugate documented that pre-production began February 7, 2023 with filming beginning on March 7, and ending on May 1.[20] It was shot at Troublemaker Studios.[21] During production, Fischbach confirmed that Iron Lung will contain the most fake blood of any horror film, beating 2013 film Evil Dead's 50,000 US gallons (190,000L);[22][23] during filming, he went to hospital due to getting too much fake blood in his eyes.[24] In a YouTube livestream posted on December 7, 2025 he revealed that the approximate amount of blood for the final movie was over 80,000 US gallons (300,000L).[21]
Post-production
On April 29, 2023, Fischbach announced on his YouTube channel that filming had been completed, marking the beginning of the editing and post-production process.[25] In July 2023, Fischbach revealed that he is a member of SAG-AFTRA, and that the production of Iron Lung would be delayed due to the 2023 SAG-AFTRA strike.[26][27] After filming was completed, Valkyrae was cast in a voice role.[28]
On October 14, 2023, Fischbach published the official trailer of Iron Lung on his YouTube channel.[29][30] On October 16, in a livestream on his YouTube channel, he stated that he had turned down a role in Five Nights at Freddy's (2023) in order to produce Iron Lung, due to the two films having conflicting production schedules.[31]
Release
In June 2024, Fischbach announced that it was "officially done", and that he was in the process of negotiating its release.[32] On December 5, 2025, Fischbach published the release date trailer and opened ticket pre-sales.[33][34] Despite an initial slated release in only 60 independent US theaters, Fischbach encouraged fans to request it directly from their local theaters, leading to a grassroots word of mouth campaign reaching Cinemark, AMC, and Regal Entertainment Group, among several others.[34][35] As of the official release day, January 30, 2026, it is showing in 4,161 theaters internationally.[36]
Iron Lung debuted in North America, the United Kingdom,[37][38] Australia,[39] New Zealand[40] and some European territories by Piece of Magic Entertainment.[41][42]
Reception
Box office
In the United States and Canada, Iron Lung was released alongside Send Help, Melania, and Shelter. The film opened with $3.5million on Thursday previews and was initially projected to make $9–10million domestically on opening weekend.[2] After an $8.9million opening day including Thursday previews,[43] projections were increased to $14–17million.[44][45] The film opened with an estimated $17.8million from 3,015 theaters per Variety and Deadline; Markiplier Studios did not report official figures.[46][47][48]
Critical response
Iron Lung received mixed reviews from critics. On the review aggregator website Rotten Tomatoes, 47% of 17 critics' reviews are positive.[49]Metacritic, which uses a weighted average, assigned the film a score of 45 out of 100, based on 4 critics, indicating "mixed or average" reviews.[50]
Eric Goldman for IGN was negative, rating the film a 4/10 and describing it as having bad pacing and low energy.[51] Mike McCahill for The Guardian, rating the film a 2 stars and calling the production "barebones" well also stating "At least MrBeast's stunts get him outside."[52] Dennis Harvey for Variety was more positive, saying "For an ostensible sci-fi horror movie from a sci-fi horror game, it could have used a wee more actual horror content."[53]
Luis Pomales-Diaz from Horror Press called it a "worthy successor in the cosmic horror genre", commenting positively about its special effects and its final act, as well as Fischbach's acting, calling it "hit or miss, but mostly hits", comparing Iron Lung to 1997's Event Horizon.[54] Alison Foreman of IndieWire similarly gave it a C+, stating, "'Iron Lung' is audacious and at times astonishingly boring. Still, it feels more enthusiastic and celebratory than many blockbuster adaptations built on safer math. Insisting that the mission is bigger than any one person, including its creator, it opens space for more daring, messy attempts to follow."[55]
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