I like the level design. The game idea is very simple (such games are of course not very unique), but the implementation is good.

I tested until the third level, so just mainly 3 critics:
1) the ball physic is not always convincing. If you roll towards and edge the ball will "jump" strangly.
2) sometimes the distance between two checkpoints is really long
3) anti-aliasing is missing..

all in all a very nice designed game. (Quality of a good freeware game)