Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. All PC updates will be coming to the 360 in a future update. The major changes include:

Left 4 Dead 2

• Encore mutation: Hunting Party
  
• Fixed double scoring bug when Survivors would incapacitate themselves in the safe room.
  
• Dark Carnival The Concert: Fixed invulnerable spot on top of the plywood.