The problem I find about most Portal-like games is how they require so much precision. With Portal, though, I got along fine. There was always another way to do things, and if I couldn't think two steps ahead, I could usually stop and think before I kept going. However, I get the feeling that Portal 2 will be different. With so many gameplay elements, and co-op mode, I get the idea that I'm going to be throwing my controller through a window trying to make pixel-perfect jumps. I like the thought behind the idea, not the execution of it.