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)