Valve announced today a sequel to one of the hottest games, Left 4 Dead 2. Slated for release on November 17th exclusively to the XBOX 360 and PC, the game looks to be a best-seller of 2009. The new game will add some new tricks to the not-so-old dog, including melee combat with baseball bats, axes, and everyone's favorite: the chainsaw. It will also have a new AI Director 2.0, which will allow for more dynamic gameplay with changing weather effects, world objects, and paths, as well as controlling the hordes of undead enemies to match your performance. The game will have new survivors, zombie bosses, weapons, items, more co-op campaigns, more versus campaigns, and more Survival Mode maps at launch. Look for cover stories of the game to hit PC Gamer and Official Xbox Magazines this month.