Looks beautiful, like others mentioned, controls could be easier. When switching gravity, controls could stay same or gravity could be switched with the jump key. I finished first two levels, than in third I picked first key and after picking a second key, I died. I didn't want to go from the start again and pick those keys again. In the first two levels, dying was ok, because keys weren't too far apart, but in the third level, it was much more difficult to obtain them. It'd be better if the game remembered what keys were picked and after death, doors switches would stay opened.
Very polished and nice to play game.