Updates to Left 4 Dead have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Left 4 Dead
  • Added Mac support for Left 4 Dead
  • In Versus mode Tanks will spawn in stasis until a human player takes over. Tanks in stasis are invisible and invulnerable, and won't move or attack
  • Tank speed is no longer reduced when on fire
  • Allow players on the Infected team to manually spawn during finales
  • Added a vote option toggle All-Talk
  • Any Special Infected that causes a Survivor to stumble into a "ledge hang" situation will receive 50 points
  • Bullets that first pass through an infected character before striking a Survivor are now ignored as friendly fire
  • In Versus mode car alarms will now trigger anytime a Special Infected pulls or stumbles a Survivor into an alarm car
  • Protected console commands that can be used to lag or crash servers