I was really impressed by the art, animation, and sound design. Great stuff!
The fact that the game's hazards are slopes and edges of various angles can make things difficult at times. It's not always clear what needs to be avoided and what can be walked on. More easily identifiable obstacles would have been really nice.
I wish the controls inverted when you were in the black zone. It was always my instinct to press down to jump when upside down.