We started playing Super Mario Galaxy 2 a few days ago and have been having a blast.  The original Super Mario Galaxy is one of my favorite games of all time and this one takes that as a solid foundation and added new mechanics and a ton of new levels.

The co-op mechanic is great for younger children.  They get to use their own controller, but instead of controlling a 2nd character on screen...they get an cursor that allows them to affect the world. They can hold enemies in place to allow Mario to get around or land on them, can pick up stars around the map and can even shoot the stars at enemies to harm them.

Kian had a blast doing this in the original game, but this time...something happened that I didn't expect.  After a day or two of playing I found out that my son had started his own game and was actually further along in the game than I was!  The control scheme used to be too complicated for him but now that he's 6, he has mastered it and now I'm the one with the co-op controller.  He does need help from time to time with the more difficult puzzles but i'm extremely amazed and proud at how well he's been doing. This development has taken the co-op experience to a whole new level for us.