Solid arcadey shoot-em-up. I won't to repeat every other comment, so just a few extra notes I have.
- It'd have been nice to be able to regain a color I've lost somehow - as it is once you lose one it both makes the game easier (because you have to pay less attention to dodging) and also make it take longer to increase score because of the dead time when the target's using I color I don't have access to anymore.
- On a a related note, there's a lack of difficulty increase - probably coupled to the problem where standing still means you shoot down all the bullets coming your way.
- It'd have been nice to have which color corresponds to which key somewhere on the screen. Probably just me, but I found it easier to keep cycling through all of them rather than try to remember.