Portal 2 (360)
Valve really have made a great game. Actually thinking (instead of mindlessly killing people by making your way through a ridiculous storyline) is a real refresher. The difficulty of the puzzles seems to range from incredibly easy to somewhat hard...but all in all there seems to be a very good balance of easy and hard puzzles. I was blown away at how different the game is with the added new gels, funnel, faith plate and co-op. Co-Op is better than SP imo.