I watched the trailer and I must say that it looks awesome! I wish I had an iPod just to play it xD
Also for an idea, you could have like an "orb" that flips the screen disorientating people. You could also have like some sort of orb that changes the whole mood of the game, the background music and the colours of everything, kinda like how pixeljunk eden works.
Good work though, I really like it