Nice visual style, but as you mentioned it's very short so not that much to rate. Adding some ambient music would really help I think, as it hads the potential to become very atmospheric.

The player physics are really harsh, making jumping a lot harder than it needs to be. Gravity is too powerful. There are also a lot of collision issues, where I'd have to jump to unstuck myself out of the floor.

I have to agree, the jumping is tough to work with. I played another game with a similar issue during this compo, and I couldn't complete his (I beat yours :] )

I believe platformers feel best when they are partially modeled on basic Newtonian mechanics. It appears that you are instantly flipping the player's velocity when he reaches the apex of his jump. It will feel much nicer if the player slows down as he reaches the apex of his jump, then accelerates on the way down until reaching terminal velocity. From there, playing with the constants is all that is needed to find the right "feel."