Sometimes, as a fan and as a critic, you have to take a step back and give a film some credit for what it is, rather than what it should be. Iron Lung, an adaptation of the videogame of the same name, directed by and starring YouTube megastar Mark Fischbach, is a prime example of this. Fischbach, better known as Markiplier, may be a nearly household name at this point for his comedy and gaming videos, but this marks his first real foray into feature-length filmmaking. While his lack of experience as a director, editor, and actor definitely impacts the film, there’s still no denying that Iron Lung is much better than it has any business being.

The film takes place in the future, when an event known as the Quiet Rapture has wiped out most of the stars in the universe and decimated the human race. A convict named Simon (Fischbach) is welded into a submersible and sent to the bottom of an ocean of blood in search of secrets that might be able to save what is left of humanity. With only a camera for visibility and no way out of the sub, Simon must contend with the dread and isolation of his mission while also tackling the horrifying possibility that he may not be truly alone at the bottom of the ocean.

Solely as an actor, Fischbach is shockingly good. There are moments here and there where he spends a bit too long staring at something with a blank, confused look that almost comes off like a joke, but most of the time he’s believable and even likeable. A film set almost entirely in a single location with little more than voices to play off of is not an easy one for any actor to handle, and Fischbach does better than I think many people would expect.

Had he stuck to just acting, the film might have been even better. He doesn’t do terrible work as a director, writer, or editor, don’t get me wrong, but it’s obvious how much a more experienced hand would have helped. The film never does figure out a good pace for the story, with some parts dragging on far too long and others rushing by. A thrilling final act doesn’t make up for how dull some of the rest of the movie is. As a writer, Fischbach clearly wanted to flesh out the lore of the universe and Simon a bit, which is admirable, but it does lead to long, melodramatic exposition dumps that can be boring to sit through.

Mercifully, the setting and cinematography are able to do a ton of good for the film, elevating it above many of its shortcomings. Behind the camera, Philip Roy does an excellent job making use of the space in the sub. It feels appropriately tight and confined, more like a prison than a vessel. Even more impressive is the world around the sub, which we never actually see. The ocean is shown only in photographs, yet it still feels very real. Simon’s hand-drawn maps give us a sense of the layout and create enough consistency that it’s easy to forget he isn’t actually in an ocean of blood.

If you were to judge the movie against its big-budget, studio-backed contemporaries, it obviously wouldn’t stack up to many of them. There are many issues, many of which can be attributed to an inexperienced filmmaker taking on far too much responsibility. Yet, for an adaptation of an indie videogame produced, directed by, and starring Markiplier, it’s an impressively expectation-defying success. Iron Lung shouldn’t be this good. Its flaws may sink it a little, but it is definitely not out of its depth.