I didn't get anything out of this. Felt very simple and not very mind-bending. Should I feel something?

Its an almost 45 year-old short story that appeared in a print collection of other short stories. The submitted page kind of loses much of that context - and possibly feels dated or simplistic because of that?

Clearly a long antecedent and possible spiritual predecessor to SCP-3008 and the Backrooms genre which recently spawned a liminal horror movie called Backrooms. It it feels derivative, that's probably the Seinfeld Isn't Funny effect. If it feels uninteresting, you're probably not into this genre.