It's a very good game, better than Super Mario Sunshine, but definatly not as good as Super Mario 64.
Gameplay: Fun I guess, I didn't really like the whole running around over planents, I mean it should taken place in like... I don't know, but Super Mario Sunshine had a better setting than this, but other than that, the controls are perfect, but.. I love Mario being 2D and I always will so I can't really give game a high review, because I enjoy Mario being 2D unless it was Mario 64 and if I review Mario 64, I'd give it a 10, but this is no Mario 64.
8/10
Graphics: Gorgeous Graphics, I think it's one of the best on the Wii, very similar to 360/PS3 graphics and everyone has to admit it, PS3/360 graphics have is certain touch to it that even if you didn't know on which system the game was coming out on, you could've known that it's a PS3/360 game, and this game had that touch.
10/10.
Story: like I said, I didn't like the whole running around across the galaxy thing, but it's fine really.
7/10
Conclusion: It's just me, I just didn't like it that as much as most people did, but still I think this game is worth buying.