This game is simply amazing!!! Come on Nintendo it's time to make Super Mario Galaxy 3 to complete the trilogy!
+: Luigi
+: Yoshi
+: return of classic enemies (Hammer Bros, Magikoopas, Lakitu)
+: difficult challenges in certain parts (the 242th star was the absolute challenge)
+: increased length, double the size of Super Mario Galaxy
+: improved graphics
-: the replacement of Rosalina and the Observatory by Lubba and the giant Mario head. The latter weren't bad, but the magic of the former was missed sometimes
-: linear maps instead of the orbit ones in SMG1
I think that Nintendo should definitely complete the trilogy with a game that would be even better than the previous two. However, this time the boss fights should be harder (e.g. the final boss with Bowser was ridiculously easy) and the green stars should be placed before the final fight with Bowser so that the game would give a sense of lasting longer. Maybe 360 stars would be a geat idea. The return of Rosalina and a renovated Observatory (together with Lubba of course) is a must. Imagine if she was playable too in some parts off the game!