AND FREE!
The Left 4 Dead: Critics Choice Edition, which contains the original game plus the Survival Pack, comes out on April 21st.
The content pack will add 12 maps, 11 existing maps and "Lighthouse" created especially for Survival Mode, also added is versus mode to Dead Air and Death Toll, the final two co-op campaigns. Survival multiplayer game mode - four players are given time to prepare before taking on hordes of rampaging undead as long as possible.