Great game. The powerups are definitely not useless, that is the best part of the game - all the ways the powerups can be combined. Personally, my favorite was Justice+Wheel of Fortune+Strength, then I just leave a minefield of shots all over.
The only down side is that the game got a little repetitive and slow around level 8. Is there an actual end to the game, or does it go on forever?
Really great game though, finding powerup combinations is a lot of fun.