http://planethalflife.gamespy.com/fullstory.php?id=157291 In a Microsoft press release this morning it was told that the Survival Pack downloadable content is set to release on April 21, just under a month from now. This, of course, is for the Xbox 360 version, but with the time and the more involved process it takes to release content via the Xbox Live Marketplace, it's safe to say that the PC edition will come no later than the 21st.The pack includes the new "Survival Mode" where players stay on a single map and attempt to survive an unrelenting onslaught of zombies and multiple special infected at one time. Eleven of the twelve Survival Mode maps are taken from the existing campaign with a new map entitled "Lighthouse" being released as well specifically for the new mode. The pack also brings Versus Mode support to the two existing campaigns that lack it as well (Dead Air and Death Toll). A new commercial version of the game will be released as well entitled the Critics Choice that includes the new content and all updates released thus far.