Much work to be done.
Rampage mode = awesome
Normal mode, however, is rather crap. Just another colour changing game.
1.) Fix up the upgrades menu. Make things there actually worth it.
2.) The main game is fast...but not furious. Most of the time you're just fumbling around to find the right button. At higher levels it's just impossible.
2a.) The cannon upgrade is USELESS. For the 25 it costs....not worth it in the slightest. Make it a shield that blocks once every 30 seconds?
3.) Tutorial. Got the basics of the game in. Not the best tutorial, but good enough to get you into the game.
4.) Rampage mode is indeed excellent. It is fast and furious, and most importantly fun.
Overall, not that good a game. No originality, little fun, no polish.