I spawned inside the floor on the second level and couldn't move.
Falling into the void doesn't kill you. Not a big deal since you can restart manually, but a bit annoying.
The UI gets messed up on ultrawide monitors, but I could still interact with it, no big deal.
If the rounded part of the character is supposed to be its head, it's moonwalking.
Using ESC or the quit button throws an error. It crashes the game, so works anyway, but it's not neat.