(Image credit: A24 / Vertigo Releasing) One of my favorite genres of film isn't a real genre, though if it was it'd be called "survivalone." It's when one person winds up in a dangerous environment and pretty much spends the whole movie alone trying to escape it. In this genre there's very little talking or exposition, you only know as much as the main character does, and instead of being told what's happening with dialogue or voiceover, you're simply shown it in long stretches of unbroken film: the "show, don't tell" rule writ large. This genre includes survival films like Cast Away or All is Lost, and lately, much to my satisfaction, some videogame-adjacent horror movies. Earlier this year it was Exit 8, based on the game The Exit 8 , where a man finds himself trapped in a repeating series of subway tunnels. And this week it's Backrooms, where a man finds himself trapped in an endless maze of dingy yellow offices. (Image credit: A24) I know Backrooms isn't, technically, a videogame movie.…