I got really bored, really fast.
At level 17 i just quit, not because it was hard, but because it was too easy, and slow. I've played this same style of puzzle game before, but for some reason yours was just boring.
At the beginning of each level I immediatly figured out the puzzle, then I just had to take the time to move the balls.
I would have liked it better if you added a mode where there is a countdown timer, which would have made getting medals more meaningful.
Still though, alot of other people enjoyed this game.