
Valve has revealed via IGN that the upcoming free DLC for Left 4 Dead will become available before April 21st. More precisely, the downloadable content will arrive sometime before the Left 4 Dead: Critics Choice Edition re-release releases on that date.
The download will finally add the Dead Air and Death Toll campaigns to the game's Versus mode, as well as boasting a new fast-paced Survival mode. It has also been revealed that 11 of the 12 Survival maps are pulled from existing materials, with the new map entitled Lighthouse.
Upon the start of a Survival match, players can explore and gather equipment for as long as they wish before summoning the zombie horde; but from the start the game lets loose multiple special attackers--a tank, boomer, smokers and a hunter assaulted the IGN source at the same time, and it was noted it will apparently be possible for two tanks to spawn at once.
Valve added that none of its testers have reached over nine minutes in a Survival match.