An update to Left 4 Dead & Left 4 Dead 2  has been released. The updates will be applied automatically when your Steam client is restarted. 
The major changes include:
L4D 360: 
- Added "The Sacrifice" content.     
L4D2 360: 
- Added "The Sacrifice" content.
- Added "No Mercy" content. 
- Game Play
⢠        Bullets that first pass through an infected character before striking a Survivor are now ignored as friendly fire. 
⢠        Fix for survivors speaking The Passing Finale lines in other campaigns.
⢠        Added a setup timer to Versus Survival
⢠        Fixed bug in Versus-Survival where a team could get 5 survivors
⢠        Removed Defibs and First Aid Kits in Realism Versus. Survivors start with a First Aid Kit, but all world spawns are disabled.
- UI
⢠        Added vote option to enable All Talk in Versus.
⢠        Added vote option to Restart Chapter in Versus.
⢠        Added the ability in the lobby for all players to vote on starting the game.
- Versus
⢠        Charger now receives 300 points for any Survivor that is insta-killed. 
⢠        Charger now receives 100 points for any Survivor that is insta-incapped by a charge. 
⢠        Any infected that causes a Survivor to stumble into a "ledge hang" situation will receive 50 points.
⢠        Tanks go into a stasis when they spawn and leave stasis when the human player takes over.
⢠        Tanks in stasis are invisible but still show a glow to the infected team. 
⢠        Tanks do not attack when they are in stasis.
⢠        Tanks in stasis cannot be set on fire or damaged.  
L4D PC:
- Fixed a few third person camera cheats.
- Added VPK audio cache support.
- Added "The Sacrifice" content.
- Added Versus Multi-Map Scoreboard
- Added the L4D2 Mounted .50 Cal
L4D2 PC/OS X:
- Game is fully playable on the Mac platform.
- Fixed a few third person camera cheats.
- Added "The Sacrifice" content.
- Added "No Mercy" content.
- Versus: Infected players will get a respawn time reduction against teams that rush.
- Removed need for Left 4 Dead 2 Add-on Support for Community Campaigns				  			  
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