The free PC and Xbox 360 download adds the Dead Air and Death Toll campaigns to the game's competitive Versus mode, and also adds a new fast-paced Survival mode. nope
The site also provided a few new details on Survival mode, revealing that 11 of the 12 Survival maps are culled from existing materials, with the new map called Lighthouse.
Upon starting a Survival match, players can explore and gather equipment for as long as they want before activating the zombie horde. However, the game will spare no time in unleashing multiple special zombies--a tank, boomer, smokers and a hunter assaulted IGN simultaneously, and it's apparently possible for two tanks to spawn at once.
Valve added that none of its testers have lasted over nine minutes in a Survival match.