Bah, I've tried out Mario Galaxy and to be quite honest, I just couldn't quite get into it. It's not fun at all and the controls are hardly that amazing or immersive. It's just so busy and cartoony and flashy, it really annoyed the crap out of me. I'm sorry for bashing it, I just really didn't like my experience with it. I played it for about 2 hours total.
It just seems to me like they really tried their hardest to get something 'wacky' crazy, like, oh man, look how we're distorting your perception of gravity!! ooo ooooooo ooooooooooo Look at all this crazy colorful stuff, and these cool star transforming things!! Oh and look at the controls!! You shake to do a spin and you aim to fire colorful star crystal thingies...