Interesting implementation of checkpoints in a type of game that wouldn't normally have them. You get a lot of mileage out of the Two Button control scheme, as well.
I think the game is lacking in terms of explaining what the goal is and how the mechanics work. I was able to work it out after reading the controls and some trial and error, but some more direct tutorialization would have been appreciated. I noticed the ball sometimes speeds up and sometimes slows down when it crosses over a path, but it was unclear to me what caused the different reactions.