A sequel to Valve's cooperative zombie shooter Left 4 Dead was just announced at Microsoft's E3 Media Briefing, slated to arrive November 17 on PC and Xbox 360.

New survivors in new locations--the trailer teases Louisiana--gain melee combat with weapons such as a chainsaw, frying pan, axe and baseball bat to fend off new zombies.

Valve promises "a much larger game than the original with more co-operative campaigns, more Versus campaigns, and maps for Survival mode available at launch." The gameplay-controlling AI Director is also ramped up, now able to change weather effects, world objects and pathways to keep players on the edge of their seat.

Check back later this week for our impressions of Left 4 Dead 2.