Valve announced the upcoming release of the Left 4 Dead Critic's Choice expansion pack. This pack promises a completely new game mode, Survival, and two new Versus mode campaigns. There is no word on whether or not these new Versus campaigns will be completely new environments, or will simply be the release of the Versus variants of the two other existing campaigns currently found in Left 4 Dead. In addition, a special release of Left 4 Dead will arrive this Spring that contains all of this bonus content already added. PC owners should delight in the fact that the SDK is still on the way, but may be a ways away.

The first L4D DLC - dubbed the L4D Survival Pack - is due for release this spring and introduces a new multiplayer game mode entitled, Survival, plus two complete campaigns for Versus Mode. A Critic's Choice Edition of the game is also heading to retail stores this spring, and will include access to all the content introduced in the L4D: Survival Pack.

In addition, for PC gamers and aspiring developers, the first Left 4 Dead release for the Source Software Development Kit (Source SDK) will allow the creation of custom Left 4 Dead campaigns that will be discoverable via L4D's matchmaking system. The SDK update is also due for release this spring, and is free of charge to all owners of L4D on the PC.