Plays just like the first Mario Galaxy. A worthy addition to Wii library.
Graphics still colorful and pleasant to the eyes, musics and sounds are as epic and catchy as any other Mario games.
The most noticeable changes Nintendo made to Super Mario Galaxy 2 are the new power-ups, and the now useful co-star mode.
The new power-ups are fun to use and play well with the stages designed for them. The control feels tight so you know when you die in the game it's your fault, but not the control's fault.
The other change is the co-star mode. A second play can jump in the game as the star and help the player in various ways. The second player now can pick up power-ups, stop enimies, collect star bits for the plays which are very helpful for the new harder stages. The second player is now fun to play as the star rather than just collecting star bits for the first player and annoy the player
with the pointer.
Super Mario Galaxy 2 is a great plateformer for solo or co-op plays. It feels moe like a expansion to the first Super Mario Galaxy than a true sequel. But it's not a bad thing at all, the more Super Mario galaxy the better.
In the end, Super Mario Galaxy is a worthy addition to the already great Wii library. Have fun.