Mario comes back, with a new trick up his sleeve.
The Good:
The game's graphics are awesome, and the music is (for the most part) great. The gameplay is fun, and easy to jump into. There's a large variety of challenges and levels for you to play through, and the new concept with gravity often leaves you upside down, sideways, and in just about every other position you can think of. This can be a little hard to control at first, but after a time, you'll be able to work just as well upside down as right side up. The levels and bosses are fun and imaginitive, and various minigames such as surfing and being blown about in a bubble (hard to explain) keep it interesting. The difficulty is easy enough to cater to most people who will be playing the game. However, there are some very difficult challenges and levels for those who are more experienced and wish to get everything in the game.
The Bad:
The reward for 100% collection of power stars was disappointing. It treats you to a second playthrough with some minor differences. Also, some of the challegnes become highly repetitive. They blatantly re-used the same world once, simply inverting the map so the right side was the left, and the left was the right! Certain challenges for those wishing to collect all 120 stars can also become more irritating than fun.
The game is an overall highly enjoyable experience, but several aspects keep it from getting a perfect score. I'd still highly recommend purchasing this game for your Wii; it should keep you busy and entertained for a long time.