I am going to disagree with Rey here, actually. I do think that Level 0 has grown to be very iconic and has basically become The Backrooms' trademark of sorts. And yes, maybe it's too broad and it doesn't specifically call out our wiki, and might get confused with something like Kane's (especially with the font being the same), but that's bound to happen in one way or another. So I don't think this is really the thing stopping the art from being a banner; and while yes, maybe there could've been ways to approach this, I do think this also a very good and iconic way to do so.
Regardless, about the art itself:
I have to say I love the post processing done here, the grain, the vignette, the ever so slight chromatic aberration, and the- … the-… Oh my god I haven't worked with Post Processing for so long I have actually forgot its name the lens bulge thing, whatever its name is, they're all very awesome!
Love me some VCR OSD Mono, obviously; tho I kinda wished maybe you had put a black border arround it for visibility.
I do have some very tiny nitpicks here, they're very minor but my OCD won't let me be cuz of them, anways:
1. The hall design could've been better. It's not bad per se, but I do think a few shifts in the walls could've made things look a bit better; tho I won't judge you cuz map design with Level 0 is a hell. Trust me, I'd know, I made a game about it and I suffered.
2. The bottom ridge thing in most of the walls seems to use the wrong material. The one at the front is fine, but the ones behind are not, idk if that's a camera thing or if you actually used two different meshes here. But in both cases something is most definitely wrong.
3. I would have loved to see the word "Wiki" or "Wikidot" under "Backrooms", preferably the latter, to indicate for the user which wiki you're dealing with exactly, but I guess it would be clear from other things like the site/account name anyways so maybe it doesn't matter that much.
In any case, I really like this. Good luck! +1 from me.