I wipe out the enemies really quick and then I have to clean up all the asteroids. I reckon you need a radar for the roids or just move onto the next stage.
The weapon upgrades really didn't feel like upgrades at all. Sure they changed colours and I was going back and forth with the single fire to double, but I wasn't really killing that much quicker and there is nothing interesting between them.
Everything else I liked though. It's beautiful visually, music suits perfectly, explosions are awesome, and I love the fluent game play. Really, game play like that makes boss fights great fun. hint hint, wink wink.