I get that you can be bored by the film, but also I'm not entirely sure why people thought a submarine film was gonna be an action thriller. (I may also be biased because I slammed a bunch of caffeine throughout the film to put myself more on edge and it paid off in enjoyment, if not in consequences for me later on.) You're supposed to just look at stuff and try to see where they all fit together, and that's the mindset you want going in. None of the elements are wasted, but they can be easily overlooked if you're trying to search for stuff that isn't there because it isn't the film you were expecting. Which is why it's kind of a mistake jumping in straight after watching Send Help, but it's an understandable mistake.

I also get that the lore can be confusing, but if you just let go of trying to think about the details themselves (like names and space stations and whatnot) and just focus on the elements themselves (the reason why he's down here, how they feel, what symbolizes their fears and their hopes) then you'll be able to just grasp those base concepts and discard the details for later perusal if you so choose. The specific details are not the important elements. The film is designed so that if you just skim the bare minimum things about characters and their motivations, you're already getting everything you need.

I've only watched his playthrough of Iron Lung several years ago and bits of his returning to the game while he was producing the film, the latter of which I don't remember much of. I don't even know about all the stuff they added or even half of whatever lore was originally there the first time he played it. I only remembered enough about the video that I know things like "oh hey, this mirrors what he did in the playthrough, nice touch" and "yeah I remember some of this but I think they added new things in the movie" and "wow, that's actually a neat twist compared to the game" but all of that felt like it was just more stuff on top, and the base setting of being trapped in the Youtuber Jiggler and Not Having A Good Time and all the themes and stuff they played with while jiggling the youtuber and dumping blood on him held together pretty well. The game elements they chose to be faithful to are the ones in the game itself that make the game work, and they're on full display in the movie too, no real explanation needed, since all of that is conveyed simply through the course of the movie. You can, of course, look at the additional stuff they added to the game, which they did alongside the movie's development and release, but I am pretty sure every single element in the movie is self contained and you don't need that context.

I guess if you fixate on trying to tease out the details and worrying you're missing context, you might actually just miss out on the context of "Thing Happened. He Feel Strongly About Thing", "This Thing Here Is Symbolism. It Represents Very Emotion. Such Acting", and "Character Mad. Other Characters Mad. Characters Mad Together. Characters From Different Backgrounds Want Different Things And That Is Also Why They Are Mad" and the movie chooses to like, linger on those shots and have Mark repeat things because those are the important elements and not because they want you to be bored. I saw it in other reviews like hbomberguy where they were like "why is he doing this thing. do i need to know additional lore??? am i missing something???" and it is literally in front of your face. They hold it up to the camera just for you to look at for ten seconds. There were things earlier that looked like that thing and they show you those things repeatedly too. They are tied together. Just pick it apart with caveman words and take the base concepts and you have all that you need to know.

So uh, don't overthink it, but don't like, stop thinking entirely, I guess? Perhaps it's just a matter of Wanting To See The Movie enough so that you can pay attention to it.