I really liked Portal 2, and as with the original, the only downside was that there wasnt more of it. It also lacked a proper "challenge" section, with non-story type maps to really challenge the brain. I also liked the challenges in the original, few steps, few portals, speedruns and so on. As much as I enjoy the storyline and storytelling, I had really hoped for some more puzzle-emphasis. That said, I havent completed the coop section just yet, and it does have some cool stuff, but so far I have a feeling its on the short side..