Iron Lung Review: A Tense Slow-Burn

First time director Mark Fischbach delivers an atmosphere of tension and dread in this unlikely horror premise.

Markiplier Studios

On April 21, 2023, Mark Fischbach, otherwise known on the internet as “Markiplier,” announced that he was stepping out of his booming YouTube career to direct and star in a movie inspired by the hit indie game Iron Lung. Fans anticipating the release of the passion project and indie game inspired movie “Iron Lung,” were relieved on January 30, 2026 after a long 3 year wait. The movie is rated R and contains a mix of slow-burn and body horror elements while playing into the discomfort of claustrophobia throughout the film.

The movie utilizes a form of horror that is rare in the modern horror scene, abandoning the trend of quick, cheap jump scares and instead relying on snowballing panic and anxiety in the viewer. The movie has a budget of $3 million and is Fischbach’s first professional project. It is overall a success, grossing $48 million, with consistent showings in theaters like Cinemark and AMC. The movie stands out for its unique take on horror and filmmaking, but its ambition also reveals some of the shortcomings of its first-time director.

Following closely to its inspiration, Iron Lung takes place in a universe where all the planets and stars have disappeared in an event called the Great Rapture. All life has ceased to survive except for a few humans on a space station desperately trying to research more about what happened. The main plot follows a convict by the name of Simon, who is tasked with traversing an ocean of blood inside of a tight iron submarine in exchange for his freedom. He is welded inside the “iron lung” with a dwindling oxygen supply, and his cramped setup consists of steering and accelerating controls. His visibility is limited to a single front-facing camera that takes distorted snapshot photos of the area in front of him, as he traverses the ocean using a map and a live coordinate display to navigate. 

I watched this movie on a Sunday evening in an almost empty theater with two other small groups of people behind me. I believe the silence in the theater assisted with the experience, as the sound design was one of the driving factors in the building tension. The iron submersible is made of shaky, rusted metal with creaking and groaning pipes lining the walls. Sounds of dripping liquid are present throughout the film, which serves as a constant, underlying feeling that the submarine is not only filling up, but is also not completely sealed off. The movie is paced by Simon’s dwindling oxygen supply, and I could feel the hopelessness and stress of survival through the screen.

In today’s horror climate, a lot of the films released are from big-name studios like Blumhouse and A24, who are notorious for releasing cheap, forgettable scares that serve nothing more than a quick cash grab. Blumhouse, which got its name by making great horror films like Get Out for only around $4.5 million, has set the standard for modern moviemaking. Only now it has become more about releasing films quickly, rather than making a quality film. Fischbach’s inspiration comes from a place of passion and prioritized making his own unique element of horror that made his movie stand out from the rest. 

Fischbach's success in creating an unsettling and heavy atmosphere is made possible by the slowness and eerie buildup of horrifying details. However, his commitment to slow-pacing was also the cause for some of the scenes to drag. With an above-average runtime of 2 hours and 7 minutes, some of the scenes felt long and drawn out rather than slow and suspenseful. Another thing that fell short was the acting. Fischbach cast himself in the role of the main character in his own film, and being isolated, he was constantly the center of attention. His dialogue sometimes felt awkward, and his passion in certain scenes would fluctuate at random, where one second he would be sitting back stressed and then the next second screaming in panic.

Fischbach’s inspiration comes from a game developed by the solo developer David Szymanski, who is known for his indie horror games which lack graphic quality, but make up for it in eerie environments and storytelling. The passion behind the project is undeniable, and the driving force behind this was to try and create a movie adaptation of something he truly enjoyed. His loyalty to the game’s horror element is present throughout the film, with the constant uneasy tension building until he finally gets a picture of the monster, proving he isn't alone. He did a great job in replicating the fear that was instilled in the game from the isolation and uncertainty of the things happening around you.

 As a longtime viewer of Markiplier’s YouTube videos, I could see that his experience with horror elements was showing throughout his film. Even with its flaws, it stands out in the current climate of the horror genre in film and could inspire change in quality or even inspire other independent, passion-driven projects in the future. Iron Lung serves as a solid stepping stone in his career, and for fans interested in slow-burn horror with deep storytelling elements, Iron Lung is definitely worth the watch.