Overall 5/5
It is very hard to find any fault with Portal 2, the gameplay is superb and gets better the more you play, while the co-op campaign is one of the stand out features, the sound and dialogue is some of the best we have heard in a game for a long time. Graphically it also looks great and performs wonderfully on the PlayStation 3; it also has the addition of Steam cross-platform co-op support for you to play against your PC and Mac friends, something missing from the Xbox 360 version.
All of this and the fact that you get Steam built in and a code to play on the PC or Mac versions of the game you can't really go wrong with the PlayStation 3 version of Portal 3. We can only say that Valve have once again excelled themselves.
