I liked the art and music, and also the starting cutscene is a nice adding. Unfortunately I couldn't go past the first level because I didn't understand very well the spiky ball mechanic and its controls.
I initially wanted to add some more screens explaining the mechanics in a more proper way, but in the end I had to cut out a lot of stuff. I'm glad to hear where I could improve though, so I'll keep that in mind for next time.