Iron Lung Review – Markiplier’s directorial debut is a creepy endurance test that horror fans will enjoy

Plot: The stars are gone. The planets have disappeared. Only individuals aboard space stations or starships were left to give the end a name — The Quiet Rapture. After decades of decay and crumbling infrastructure, the Consolidation of Iron has made a discovery on a barren moon designated AT-5: an ocean of blood. Hoping to discover desperately needed resources, they immediately launch an expedition. A submarine is crafted, and a convict is welded inside. Due to the pressure and depth of the ocean, the forward viewport has been encased in metal. If successful, they will earn their freedom. If not, another will follow. This will be the 13th expedition.

Review: We live in a pretty fascinating era in which popular digital creators are venturing beyond their usual formats and stepping confidently into legitimate filmmaking. We have seen the Philippou brothers of RackaRacka stun audiences with Talk to Me and Bring Her Back, Chris Stuckmann make the leap with Shelby Oaks (albeit with less fare), and even more recently, Curry Barker move from That’s a Bad Idea sketches to his feature Obsession. With that trend in mind, it felt inevitable that Mark Fischbach, better known as Markiplier, would eventually journey down the same path. This is especially true given the ambitious story of his web series In Space with Markiplier.

If you’re reading this, there’s a good chance you have seen some of his content. If anything, you have at least heard the name. I could lie and say my familiarity comes from my son watching these types of YouTubers daily, but in all honesty, I first stumbled onto him about 11 years ago because I was a grown-ass adult playing Five Nights at Freddy’s, and here was this other grown-ass adult geeking out over the exact same game.

That shared history makes his directorial debut, Iron Lung, feel like a genuine evolution rather than just a novelty act. Adapted from the indie horror game of the same name by David Szymanski, this is a passion project in the truest sense. It’s the kind of thing that clearly ate three years of someone’s life to get right. And honestly, adapting Iron Lung is a huge challenge because it is not a story-heavy game in the traditional sense. It is built entirely on isolation and the dread of doing a job you are not meant to survive. He was not just adapting a plot; he had to adapt an experience. And I’m pleased to report that you can sense all the blood, sweat, and tears he put into this on-screen.

For those wondering if you need to play the game to understand the movie, not really. The film stands firmly on its own. The smartest thing the adaptation does is stick to the game’s core mechanic: the sub has no windows. To see where he’s going, Simon has to snap a grainy black and white photograph, wait for it to develop, and pray nothing is staring back at him. It turns every camera flash into a game of Russian Roulette and forces the audience to feel the same blindness as the protagonist.

The set design and cinematography are the first major indicators that this is a serious piece of filmmaking. The submarine establishes a suffocating claustrophobia that never lets up. It’s all grimy metal and machinery that looks like it is one bad decision away from imploding, with blood dripping from the cracks. The sound design is equally impressive, leaning into a “less is more” approach regarding the outside threats. Instead of constant monster reveals, the movie uses sounds like creaks, groans, and alarms to let the horror play out in your imagination. To go along with that soundscape is a fantastic score by Andrew Hulshult, who did the music for Doom: Eternal, which fits the industrial dread perfectly.

And yes, I have to talk about the blood. Fischbach has openly hyped the fact that Iron Lung used a record-setting amount of fake blood, previously held by 2013’s Evil Dead, and I am here to tell you that it shows. This is not just splashy horror blood used for a gross-out gag. The blood is the environment. It’s oppressive and ever-present, lending the ocean and ship a sense of life and weight, especially in the film’s climax, where it adds body horror.

The lighting also deserves a special shout-out. In this day and age, horror films tend to be over-lit and afraid of the dark. Iron Lung embraces a grimy analog aesthetic that reminded me of the tactile dread of Dead Space or Alien: Isolation. Not because it’s copying those worlds, but because it understands the same rule: what you can’t quite see is often more terrifying than what you can. It’s not just the shadows, though; it’s the texture. We see Simon physically wrestling with rusting valves, toggling heavy switches, and reading analog gauges. It grounds the sci-fi elements in a gritty, lived-in, decaying reality.

Most of all, I have to praise the acting chops of Mark Fischbach. To wear so many hats like writer, director, financier, editor, and star is without a doubt a heavy burden. It could have easily turned into an ego project, but that never happens here. He sheds the high-energy internet persona and anchors the film with a surprisingly grounded performance. It’s not YouTuber acting. It’s the shaky resolve of a man trying to survive a job designed to kill him. Even though Mark is the only face we see for the vast majority of the runtime, he’s not entirely alone. The voice acting from the supporting cast helps flesh out the world outside that metal coffin, adding layers of bureaucracy and desperation that make the lore (yes, I went there with the lore) feel massive without ever showing it.

However, my sole and primary criticism lies with the pacing. I feel like at least 20 minutes could have been trimmed without affecting the movie, and it would have been a near-perfect pressure cooker. The trade-off, of course, is that the length also contributes to the film’s mission statement: you’re meant to feel the time, the repetition, the ritual of the task, the slow grind of paranoia. Whether that plays as hypnotic dread or “could’ve been tighter” will depend on your tolerance for slow-burn confinement horror. That said, I have to give props to the technical editing. While the runtime is long, several transition shots were outstanding, visually blending the nightmare of the sub with Simon’s past in a way that felt incredibly creative.

I am just not sure how the film will play for the general audience. If they are looking for anything beyond a man in a tight metal box, they might be disappointed. Aside from a handful of flashbacks, we never leave the submarine, putting this in the same experimental lane as Buried or Locke. But if you are willing to stick with the ride, Iron Lung becomes a gripping endurance test. There is no doubt his fans will show up and enjoy every second, but what impressed me most is that he does not pander to them like Five Nights at Freddy’s. There are no winks, cameos, or fun callbacks. Instead, he delivers a serious and uncompromising descent into the depths of the blood ocean.

Iron Lung is out in theaters now.

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