Iron Lung (film)

Lore & Background

Development on Iron Lung began in April 2023 when Mark Fischbach announced he would adapt the game into a film, having previously played it on his YouTube channel. He wrote, directed, and starred in the film alongside Caroline Kaplan, with David Szymanski assisting with the story and appearing in a cameo. Filming commenced in Austin, Texas, and was completed by April 29, 2023, though post-production was delayed by the 2023 SAG-AFTRA strike.

Reader's Guide

Iron Lung represents a significant milestone for Mark Fischbach, transitioning from online content creator to feature film director. The film's grassroots release strategy, initially in 60 independent theaters, expanded to 4,161 theaters worldwide after fan requests to major chains. Despite mixed critical reviews, it achieved box-office success with $51 million globally. The film's plot explores themes of isolation and cosmic horror, with a notable use of practical effects and a record-breaking amount of fake blood. Its legacy includes a partnership with blood donation centers during release, aiming for a world record of 37,000 donations.

Did You Know?

• The film was self-released in North America on January 30, 2026.

From a Joke to a Feature: Development and Creative Vision

The path from a 2022 indie video game to a 2026 theatrical feature began almost as a lighthearted aside. On February 16, 2023, game creator David Szymanski posted a playful tweet suggesting that YouTubers Markiplier and Jacksepticeye—both of whom had already played Iron Lung on their channels—would star in a film adaptation scored by Andrew Hulshult. What started as humor quickly took shape. By March, Markiplier confirmed in a Variety interview that he was writing, directing, and acting in an unnamed project. By May, McLoughlin publicly verified his involvement. Szymanski went far beyond a passive rights-holder, embedding himself in pre-production to shape the screenplay and spending time on set during principal photography. He even filmed a brief cameo as himself. Hulshult was attached to compose what would be his first-ever film soundtrack. The entire production was self-written and self-financed by Fischbach, making it a deeply personal creative endeavor rather than a studio-backed adaptation.

The Story of Simon and the Iron Lung

Set in a far future, the film opens with the "Quiet Rapture," a catastrophe that erases every star, inhabited world, and human being simultaneously. Only barren planets and the few people aboard space stations or vessels survive. Simon, a convict punished for destroying Filament Station, is exiled to a newly discovered moon and forced to pilot the SM-13, a submarine nicknamed the Iron Lung, through an ocean of blood. His only sight is a crude still camera; his only contact with the surface is a limited radio. Freedom is his promised reward. The descent uncovers a vast skeleton, a seed medallion and voice recording from a previous pilot, and a living creature that attacks the sub. A woman's voice—commander Ava—guides Simon toward a luminous "light" below. Data from a wrecked sister vessel, the SM-8, reveals the ocean is human blood and the light is tied to the Rapture. In the climax, Simon refuses the monster's command to destroy the data. The medallion's seed erupts into a giant tree that kills the creature as the submarine implodes. The black box, lashed to a life vest, drifts to the surface, found by an unseen party.

An Ensemble of Voices and Online Personalities

The cast blends established voice actors with well-known internet personalities, reflecting the film's origins in gaming culture. Markiplier portrays Simon, the convicted pilot, while Caroline Rose Kaplan plays Ava, the surface commander whose vessel is ultimately destroyed. Troy Baker takes on the role of David, and Kazuki Jalal appears as a younger version of Simon. The film's most distinctive casting choice is the sea monster, whose voice is shared between Elsie Lovelock and Elle LaMont—each of whom also appears on screen as a researcher aboard the SM-8. Mick Lauer provides the voice of the previous occupant of the Iron Lung, while Seán McLoughlin, better known as Jacksepticeye, appears as Jack. Alanah Pearce lends her voice to a "Familiar Voice," and David Pettitt and Holt Boggs round out the principal cast as the Father and an Eden Soldier, respectively. Beyond the main cast, additional voice contributors including Rahul Kohli, Ethan Nestor, Valkyrae, Mika Midgett, and Robert Rexx populate the film's audio landscape. Creator David Szymanski also makes a brief cameo as himself, tying the adaptation back to its source material.

Release, Reception, and Box-Office Performance

Iron Lung reached North American theaters on January 30, 2026, distributed entirely by Markiplier himself rather than through a traditional studio pipeline. The film was an independent science fiction horror production and marked Fischbach's feature-length directorial debut, a significant step beyond the YouTube content that had built his audience. Critically, the film received mixed reviews, with commentators split on its execution as a genre piece. Audiences, however, responded far more enthusiastically at the ticket booth. The film grossed $51 million worldwide, a result that qualified as a clear box-office success for an independently financed, self-released feature. That commercial performance was especially striking given the project's roots in a 2022 indie video game by David Szymanski and its development as a self-written, self-financed passion project rather than a studio slate title. The film's audience likely drew heavily from two overlapping communities: fans of the original game and the broader YouTuber ecosystem surrounding Markiplier and Jacksepticeye. Seeing both creators share a screen in a cinematic context added a layer of novelty unique to this project. The self-release model also meant the production retained full control over its distribution, a choice that underscored the project's independent spirit.