The demo is SUPER outdated for what the game is rn, so most of your criticisms have been fixed
-there are wall textures, along with much better graphics
-movement takes a bit of getting used to since it’s physics based, not entirely sure how to fix that
-overlapping voice lines have been fixed
-checkpoints have been added
-Oh yeah… that’s Gary the quantum door. I thought I fixed him. Guess not
-falling out of the map is much more difficult now