hansamurai writes "Left 4 Dead 2 has been announced at E3, and a trailer for the game has surfaced. It will be released November 17, 2009, just a year after the first game. Gameplay changes include a new focus on melee weapons, especially the iconic anti-zombie weapon, the chainsaw. The cast of characters is brand new, but the plot appears to take place during the same zombie outbreak." The game is being developed for the PC and Xbox 360, and Valve says it will make use of a new version of their AI engine, which has the ability to "procedurally change weather effects, world objects, and pathways in addition to tailoring the enemy population, effects, and sounds to match the players' performance." Rock, Paper, Shotgun got the chance to do a hands-on preview, providing details about the gameplay and confirming that "it's a coherent new imagining of the game, this time bigger, smarter, and far more elaborate. Oh, and gloriously more gory."