Overall the game is executed well, but there are a few tiny things that keep it from being great. The first one is that its hard to compare scores with other people because of the star system. Some people might value the stars, some might value the score. Theres no overall score for each run.
The largest problem Ive run into while playing this game is that when you hold down one side, you have to lift both fingers before making contact with the other side and changing the direction of your ball. In theory clicking either side should override the other. They shouldnt cancel each other out and leave your ball motionless.
The soundtrack aims to be too dramatic and ultimately dulls the gameplay.