Loved the game. I keep dieing trying to do more and more awesome stunts... (I mean this as a complement - the game is so fun, that you forget about the whole goal thing, and just want to jump!) If you play conservatively, its not that hard to make it through - you'll just get a lousy rank.
However I was let down by by the boss. After you destroy his four cannons and lasers, the boss moves down the screen and you're meant to jump in... didn't realise this was what I was meant to do first time around, so sat around wondering "wtf" until the time ran out. What would have matched the theme of the game better would have been to start off the boss level by blowing up the boss/planet - but then you have to out run the shockwave, having to jump from fleeing ship to fleeing ship (that should have the same reckless charm the rest of the game has).