'Iron Lung’ Review: Markiplier’s Directorial Debut Is a Promising, But Slow Descent Into Horror

YouTubers turned filmmakers aren't a trend anymore. It's a new normal. Gone are the days of Fred: The Movie or Smosh: The Movie; now we have films like Talk to Me and Shelby Oaks. In the case of those latter two movies, those creators completely changed their brand on the internet. Their content now is far different than what it was when they initially started. That's what makes Mark Fischbach (better known as Markiplier) an interesting case. He's been making let's plays and comedy videos on YouTube for over a decade now, and his fanbase has always been loyal to him. He's branched out into making other types of videos, but nothing on the level of Iron Lung.

Iron Lung has an interesting history. It's based on an indie horror game by David Szymanski, which has a cult following. It's also not one of those indie titles that broke into the mainstream like a Five Nights at Freddy's or a Minecraft. It's got a small but strong fanbase in the grand scheme of things. Fischbach, of course, played the game on his channel, and back in 2023, he announced he would be self-funding, writing, directing, and starring in a film adaptation of the game. Things had been quiet on the film for a while, until last month when Fischbach announced that he would be self-distributing the film, giving it a limited release. Of course, plans changed, and fan demand was high enough that the movie was given a full wide theatrical release.

What Is 'Iron Lung' About?

Much like the video game, Iron Lung is set in a post-apocalyptic future, where all the stars and habitable planets in the universe suddenly disappear in an event known as "The Quiet Rapture." Simon (Fischbach), a convict looking for redemption, is sent on a mission to explore an ocean of blood that was found on a moon. Aside from a few flashbacks, the entirety of the film takes place within the confines of the small dinghy submarine, nicknamed the "Iron Lung."

As Simon continues his mission, which involves the discovery of some sort of alien fossil, we begin to learn more about his tragic past, including his involvement in a tragic incident at a space station known as Filamnet Station. There are some big twists, and to reveal anything more would ruin part of what makes the film work so well.

'Iron Lung' Is the Definition of a Slow Burn

Image via Markiplier Studios

Iron Lung has a runtime of 2 hours and 7 minutes, and you feel every second of it. Fischbach isn't trying to go the route of making a campy or commercial horror movie. The story's lore is fascinating, setting up lots of different ideas and mythology that make the movie more compelling. That doesn't prevent the film from being incredibly boring at times. Because of the budget constraints that come with making such a small-budget movie, it makes sense for Iron Lung to take place in one location. Simultaneously, the movie shouldn't have been nearly as long as it is. There are many scenes that could have easily been cut, including multiple elongated sequences of Simon toying with the submarine's lightfixture or yelling and cursing at the voice on the intercom. You'd still have the same impact with a 90 or 100-minute runtime, as opposed to a 127-minute epic.

Fischbach also just so happens to be the editor of the film, and while he's directed digital interactive short films, you can tell he's still ironing out the kinks and quirks of making a feature-length movie. As a director, he shows a lot of promise. It's incredibly admirable that, for his first attempt at a big-screen movie, he chose to make something that feels so alienating. He has a massive fanbase, and some of those fans might not be as taken with the movie.

Fischbach makes plenty of impressively cinematic decisions, including effectively building a sense of dread that just won't quit eating at you. While many may be used to seeing him yelling at a jump-scare while playing a video game, Iron Lung rarely implements that tactic. There are moments where you think it's going to, but it holds back. He generates fear from black and white camera shots on the submarine's computer, showing the creatures that lurk in the bloody ocean.

'Iron Lung' Feels More Like an Experiment Than an Actual Movie

Image via Markiplier Studios

As well as Fischbach can conjure up those emotions of dread, he should have let someone else be the star of the film. His performance isn't bad, but when he's mainly the one person we're seeing on camera for two hours, the cracks show. He appropriately sheds his YouTube persona to play a quieter and more understated character, but he doesn't feel like a real person. It was clearly Fischbach's intention to make Simon more of a POV character, but it also makes the sluggish pacing more noticeable.

Iron Lung plays more like an experiment than an actual feature film you'd see on the big screen. That's not a bad thing, as it makes it play out similarly to how the video game does (a point-and-click game). The attempts at giving Simon more of a backstory fail to strike up any emotions, but you do get a full sense of his dread as he comes to the realization of his true fate.

With all the production limitations that Iron Lung faced, the fact that it is as effective as it is feels like a miracle. If Fischbach plans on continuing to venture into making movies, it'll be fascinating to see what he does next. Iron Lung is far from a perfect movie, and the pacing ultimately makes the conclusion feel exhausting rather than exhilarating or shocking. You'll be ready to leave once the credits roll. Yet, the craftsmanship is there; with his directorial debut, Fischbach shows that he's more than just a YouTuber, and he can conjure up the same kinds of scares that make him scream as he's playing games.

Iron Lung is now playing in theaters.

Release Date January 30, 2026

Runtime 127 Minutes

Director Mark Fischbach

Writers Mark Fischbach

Producers Will Hyde, Amy Nelson, Jeff Guerrero

Cast

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  Mark Fischbach

  Speaker #2 (Voice)

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Pros & Cons

• Markiplier effectively brings a sense of underlying dread that haunts the entirety of the movie.
• For such a low budget, Iron Lung still feels incredibly cinematic.
• Fans familiar with the game will be pleased with its accuracy.

• You feel every second of the 127-minute runtime thanks to the sluggish pacing.
• There are multiple scenes that could have easily been cut.