good game, but the gameplay doesn't REALLY depend on the music itself... All I had to do for lvl 1 was keep right arrow pressed and keep jumping, 2nd one was just watching the blocks (that come down randomly, not to the beat) and 3rd one had, again, randomly poking spikes. I liked though how for the boss stage the music becomes all quiet when you can stomp him
for lvl 8 perfect, keep trying and time your last rush with the flying balls so that the ball comes between the choppa and the upper wall in the cave. just... keep trying!
wow, I've been playing for the hard badge and when I was done, the screen seemed to move up on its own even if everything was still... @_@ I had too many chains lol
pro-tip: just body-check into a boss when your special is full (get some special minions for boss battles), and press space bar when you're "on top of" the boss. massive dmg