Portal 2 co-op reminds me more of the original Portal than anything. The co-op game focuses way more on straight testing than story which make...

The "Perpetual Testing Initiative" has been expanded to allow you to design co-op puzzles for you and your friends!
Yeah the puzzles definitely require a little more thinking but you feel way less ridiculous talking through the solution with a friend than when you're talking to yourself in single player.
Hahaha, very true.