Really cool concept, the music fit the vibe quite nicely too ! I also got stuck, in the 4th room I beleved, i tried to pass by the door on the floor, struggle to pass trough it, i did manage by messing with the physic but then i was stuck on the ceiling, walking on my head i guess, unable to reach the next door that was on the wall :O
(Funny enough, i did mess around with the idea of the upside down with my game too :D)