Backrooms kinda started with the abandoned furniture store looking stuff. Then it started getting mixed in with the Dream Pools liminal space stuff. So now I’m just starting to see concrete pool mazes as “Backrooms” environments. So, hence, Moist Brutalism.

Did a bit of searching which took me to the descriptions of brutalist architecture, with examples. It makes a lot more sense to me now and see what you mean. Brutalist architecture does have that sort of liminal space kind of vibe to it.