By my trousers, Trine is my favorite kind of co op game. Each player has different abilities and they must work together to complete puzzles. You can play it alone, but with online multiplayer added, why would you ever want to? The puzzles are harder, the levels are longer, and I love all of it. Still haven't mastered that damn fireball spell...

Lets face it. there's no way you're on the fence about Portal 2 you either have it or you can't get it/ don't want it and nothing I can say will change that. I'm going to blab about how great co op is. the co op is so much fun! I love figuring out a new puzzles with someone. Also, gestures are awesome. Every co op game should have them.

The Orange Box: part 3: After completeing Half life 2 and the episodes all that was left was TF2. This was the first online multiplayer game I ever played. I remember taking my first few steps into a server, intimidated by the idea of playing a game with people I can't see, Hearing the scout say one of his lines, and freaking out, thinking the scout was another player, lol, it's funny thinking back. Team fortress 2 introduced me to a love of flamethrowers; and eventually Kross. I love TF2 because it's actually a really funny game, and can also challenge your skills. Not to mention all the free updates. It's right up there at the top of my favorite games of all time list. (right below Little Big Planet, lolz) Ironic, the game I thought I'd like the least in the orange box goes on to leave all the others in the dust.