Portal 2 is different from most other video games. The aim, instead of being to shoot enemies or defeat the opposition/enemy in other ways, you have to complete puzzles in order to escape a sinister science laboratory with a sarcastic evil computer as your enemy. The only way to complete each puzzle is using 'The portal gun' which fires two portals. anything that goes through one portal (including yourself) will come out the other one.
With good graphics and varied interesting puzzles, Portal two is a very good game and I would rate it: 8/10.