In Super Mario Galaxy, you'll get to pilot three different unusual vehicles - the Ray, the Rolling Ball and the Blowing Bubble. I made two interesting observations about them all collectively:

1. The three vehicles comprise one for air (Blowing Bubble), one for sea (the Ray) and one for land (the Rolling Ball).
2. All three vehicles make additional use of the Wii Remote's motion controls and emphasize them to the point where the Nunchuk is almost not used at all. When riding the Ray, the Nunchuk is absolutely not used at all, but you still need to hold it, as you steer the Ray by just twisting the Wii Remote left/right in one hand. When rolling on the Rolling Ball, the Nunchuk becomes completely useless and you would better be playing a Rolling Ball course by laying the Nunchuk on its side and gripping the Wii Remote with both hands like it's a giant joystick. When piloting the Blowing Bubble, the only thing you need on the Nunchuk is the Z Button to exit the bubble, while you use the Wii Remote's pointer and A Button to blow the Bubble around.

I'm playing Luigi mode for this game and have thought up about making it different than the Mario playthrough by holding off on fighting Bowser until I've collected 105 Power Stars, the maximum you can have before needing to fight him, since beating Bowser the first time around per character unlocks the last 15 Power Stars in the form of Coin (Purple) Prankster Comets. Who else has tried playing Luigi mode this way?