Critics Pan IRON LUNG While Markiplier’s Horror Film Cleans Up at the Box Office

When Mark Fischbach, better known as Markiplier, announced he was adapting Iron Lung into a feature film, expectations were all over the place.

Now that Iron Lung has hit theaters, the reaction is just as split. Critics are coming down hard on the film, while audiences are showing up in force and keeping it afloat at the box office in a way few indie releases ever manage.

Markiplier’s feature directorial debut arrived with surprising muscle. The film opened on January 30, 2026, in 3,015 theaters and pulled in $17.8 million during its opening weekend. With a reported production budget under $3 million, the worldwide gross has already climbed to $20.8 million.

That’s a wild result for a bleak, boring, claustrophobic horror movie that runs 2 hours and 7 minutes and carries an R rating.

Critically, the story is a lot rougher. On Rotten Tomatoes, Iron Lung sits at a 44% Tomatometer score based on 16 reviews. Critics repeatedly zeroed in on the film’s length and pacing, arguing that the concept couldn’t stretch to feature length.

Dennis Harvey of Variety wrote, “There’s not a lot of plot here, certainly not enough to sustain a full two hours. And those previously unacquainted with the game are likely to make little sense of the few things that do happen.”

Mike McCahill of The Guardian was even harsher, rating the film 2 out of 5 and stating, “Fischbach… can’t pull off the dramatic heavy lifting required to convert a short film’s worth of plot into a watchable feature.”

Nate Adams of The Only Critic handed it a “C” and added, “Trimming at least thirty minutes from the final cut… would have honored [the game’s structure] better.”

Jack Martin of FIlm Feeder said: “The lethargic editing sadly brings the film down a few pegs, because while there is a lot to admire about Iron Lung in terms of how it’s shot and performed, especially within such a confined setting, the pacing does leave you feeling rather bored.”

Eric Goldman of IGN Movies wrote, “For far too long, we watch Fischbach turn knobs. We watch him look at screens. We watch him write down things. And sometimes, we watch him argue with voices on the other side of the radio. But it’s very rarely engaging.”

Carla Hay of Culture Mix shared, “Incoherent and relentlessly dull, Iron Lung (written by, directed by, and starring YouTube personality Markiplier) is a misguided horror movie based on the video game. When will social media stars learn that on-camera fame doesn't equal filmmaking.”

Alison Foreman of IndieWire noted, “Iron Lung is audacious and at times astonishingly boring. Still, it feels more enthusiastic and celebratory than many blockbuster adaptations built on safer math.”

I’m honestly closer to that camp. I personally did not like the movie and found it way too long, painfully boring and empty. While I didn’t like the movie, I do respect what this indie film managed to pull off. I mean, a bad indie film managed to get a wide theatrical release and have a strong run at the box office!

Where things really flip is with audiences. The film’s Certified Fresh audience score sits at 89%, based on more than 1,000 verified ratings. That’s a massive contrast to the critical response.

One viewer wrote, “The acting, from Mark, to the voices over the speaker are fantastic… the tension [built] until the insane conclusion.” Another went even bigger, saying, “One of the best movies I’ve seen in a long time… Some of the best cinematography I’ve ever seen for a movie.

Critics see a thin premise stretched past its breaking point. Fans see a grim, atmospheric descent that commits fully to its oppressive mood.

Whether you find it dull or hypnotic probably comes down to how much patience you have for silence, darkness, and a very boring slow-building story to nothing interesting.

Either way, Iron Lung has already carved out its place as one of the strangest box office success stories in recent horror memory. Love it or hate it, Markiplier just proved that a fiercely independent film with a dedicated fanbase can still make serious noise in theaters, even while critics sharpen their knives.