Available for both PS3 and Xbox 360, Portal 2 is the sequel to the massively popular and critically acclaimed Portal. If that means anything to you, then you don't need to know anything more than this: it's at least as good as the first one, with less cake and more potato. If that doesn't mean anything to you, go ahead and keep reading.
Your heroine, Chell, wakes up after an unspecified amount of time in suspended animation, and is tossed headlong back into the Aperture Science laboratories, assisted by an amiable idiot AI, Wheatley. This time escape is even more difficult than before, especially when your old nemesis GLaDOS gets in on things. There's also a lot of the history of Aperture Science revealed through the recordings of its founder and former CEO, Cave Johnson (brilliantly voiced by J. K. Simmons).
Portal 2 keeps the same puzzle-based structure and the titular portal gun, but adds some new features. Repulsion gel adds lift to your jumps, propulsion gel increases your momentum (in lovely shades of blue and orange to match your portals), and conversion gel makes any surface capable of supporting a portal. Then, of course, there's the new co-op mode which allows you and a friend to play as robots working together.
Superb writing, dark humor, and creative manipulation of physics make this game well worth playing. If you are able to play this, you should do so.