Hey, I got stuck in a spiraling staircase (I suppose near the end?). You should be more careful when placing those things, or at least have a back-up plan (like a key that resets your position? local checkpoint system or something) for when these things lack polish.
Also, the world outside should have a directional light consistent with the skybox, I think. And lighting in general should be better, since I mostly see black walls.
Finally, you should either make movement more fun (whatever that means in the context of the game), or give the player a lot more to look at while walking. Almost every game of yours I've played (haven't played Brutalism Prelude yet) seems to rely on several minutes of holding W+Shift to go forward with nothing interesting going on.
These are my impressions, anyway. I like what you're trying to do, I just feel that there are several issues distracting me from the core.
Good luck with the future projects, though, looking forward to them. :)
P.S.: Getting a bit of air and vegetation felt good.