As noted on the Left 4 Dead Blog, a new automatic update for Left 4 Dead is now available through Steam, adding Mac support to the coop zombie shooter among other changes. Word is: "OSX users rejoice, you can celebrate Halloween in style. Left 4 Dead is available for Mac users everywhere. What does this mean for Mac users? You get Left 4 Dead and all the previously released DLC for one low price. Plus, thanks to steam play you can play in the same games on the same servers as PC users." In celebration, Left 4 Dead is on sale for a 50% savings. The change list for the new version follows.

• 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