Now as much as I have been let down by the Wii, Galaxy looks amazing and it is only becoming more amazing, especially with this little treat.
Now, it's a given that Bowser is the last boss in the game, but here is a special bit on info, if you beat him with all 120 stars you will unlock a mode in which you play as Luigi, now like always Luigi is much faster and jumps higher, but the game also is much different when you play as him, as well as that the game is said to be much harder with Luigi, so not only are you getting to play as the younger brother but you also get a hard mode.
Edit: Apparently only after you've secured 120 stars, completed the purple coin missions, and defeated Bowser a second time can you play as Luigi.
Now, it's a given that Bowser is the last boss in the game, but here is a special bit on info, if you beat him with all 120 stars you will unlock a mode in which you play as Luigi, now like always Luigi is much faster and jumps higher, but the game also is much different when you play as him, as well as that the game is said to be much harder with Luigi, so not only are you getting to play as the younger brother but you also get a hard mode.
Edit: Apparently only after you've secured 120 stars, completed the purple coin missions, and defeated Bowser a second time can you play as Luigi.