REVIEW: Portal 2 (Xbox 360, PS3, PC)

The original Portal was a cult smash, turning legions of shooter fans away from their AK-47s and making them don their thinking caps instead. A fiendishly inventive puzzler, it was also hilariously written, with each enigma solved bringing you one step closer to yet another killer punchline. It was a magic formula, and one that many argued would not serve a sequel well. Can Portal 2 live up to its lofty predecessor?