Valve announces the Windows edition of the Left 4 Dead Survival Pack is now automatically available via Steam. The pack adds the new Survival mode, 16 maps. leaderboards, seven new achievements, as well as bug fixes and other changes. They also announce both the retail and Steam versions of the game (PC and 360) are now available for a special price. Sure enough, the price for Left 4 Dead on Steam has been lowered to $39.99 and even lower sale prices can be found in stores right now.