Loses a star for making me hold down the mouse button for no reason (I never want to stop firing). Loses another for not letting me switch weapons with Q and E, AND not letting me remap the keys. 3/5.
Getting 3 stars on every level is way easier than buying all ships or weapons - I beat the game using the helicopter and the sound gun, then finished getting the stars with the frag launcher.
The rocket seems out of sequence and out of cost - it's really expensive, but does less DPS than a plasma shot for the same level. I don't see why anyone would ever field it.