Okay, first of all, even though I followed the development process, that knock still scared the living hell out of me, the door is on my right, so it hit the spot.
I don't know if the graphic style was a conscious choice or not, but it begin to hurt my eyes real fast, and it made it really hard to navigate in the room with the "labyrinth". I don't have much experience with 3D, so unfortunately I cannot give any advice, just point out what I saw. The edges or the models had this weird ripple while I was moving, like looking at low-res pixel art in 3D, and the desk to the left in one of the first identical rooms was vibrating as is the room was constantly clipping through it.
If you resolve the visual disturbances and maybe add some kind of a simple narration (voice or text), this has the potential to be real fun.