Been a while since I played this game. Nice to see the procedural generation, so let's start with discussing it:
It seems to be working fine, the levels are huge and the generation patterns are not obvious (although there are some rooms that may be repeated). However, there's still not much going on there. I know that this is just a demo, but if you want to go procedural, you need to refine the generator to make things interesting. The third level defeated me - I wandered around pointlessly, unable to find the exit. Maybe once you add the story, it will be easier to generate the fun stuff.
Now, besides level generation:
I just love that yelling enemy, that was totally creepy
You have to do something about the crawling corridors, since there's nothing going on while passing through them. You seem to have started improving that experience by adding that shriek, but that's just one, add more! Also maybe some corridor wind sfx? Some camera change?
And finally bugs/features
The BG is sometimes glitchy. Notice the red lines in the top-right part of the screen. Maybe the generator places it incorrectly?
At the start of the levels, the MC often gets stuck in that pose, until I jump (picture below)
