Cool game, interesting concept with the colored tracks, well presented!
Here are my complaints though
1) Having to grab the mouse to go to the next level through the level selection screen instead simply having like press enter to go to the next level.
2) the difficulty progression is tediously slow and boring, the whole first column of levels offered no challenge at all.
3) The music restarting again in each level was annoying, hearing the beginning of the same song every 10 seconds
4) And my biggest problem, loading the level "Invaders" crashes my browser 100% of the time so I can't play any further level. I won't take any points for that, it's possibly just me. but maybe you wanna check that on different browsers. I'm on IE 7