Simple, effective and addictive.
Sat down to try the game for 15 minutes and ended up playing for an hour. Smooth controls and pleasing aesthetics makes this an easy game to pick up; the rapidly increasing difficulty and satisfying gameplay make it difficult to put down. The only things I can think of to improve the experience is a way to view your own and other peoples high scores and add optional alternate controls for colour changing using the keyboard.
4.5/5 Stars.