Pen mode: touch the screen to look, double tap to jump, d-pade to move, L to shoot.
Dual mode: d-pade to shoot, use the ABXYLR.
Touch Mode:Much like pen mode but with your thumb.
My faavorite part as well. i was waiting for him to make a reference to Super Monkey Ball, or at least Marble Madness. i'm guessing he used the stylus for demonstration purposes. It would be much more natural using your finger.
Wow...After seeing this video I'm not too worried about the game's controls. It seems like it should work out pretty well. Anyway, much better than I expected.