Really cool idea for the theme! I think it's one of the more unique ones! I also really enjoyed the music it really fitted the theme! (and was really relaxing). Also the little effect that you see eyes of square was really cute!
As also CapitolJay mentioned it was hard to get around the corners.. Maybe try to have smaller colliders or that players always moves by one unit. I don't know if it would work for you implementation but something along those lines