“The Left 4 Dead Survival Pack is now available for the PC and Xbox 360, free of charge to all owners of the game. The full change list for the PC release is below. In addition, both the retail and Steam versions of the game (PC and 360) are now available for a special price. Check Steam and local retailers for pricing details. For more information about L4D, please visit www.l4d.com

Survival Mode

• New gameplay Mode
• 16 maps including Last Stand
• Leaderboards
• 7 new achievements

Versus Changes

• 2 new versus campaigns
• Fixed a case where versus team score would continue to be recalculated after the score panel was displayed
• Fixed an issue with recalculating the versus score health bonus for a player when they are rescued from being incapacitated
• Fixed being able to start a swing as an infected, then teleport to the survivors and have the claw swing hit a survivor
• Fixed a case where teleporting to the survivors would not reset the ability timer
• Fixed an exploit where you could load the chamber of a weapon with bullets by holding down the melee key
• Fixed a case where it was not possible to join a game while it was in a finale
• Fixed a rare case where listen servers would speed up the game over time
• Removed convars related to melee fatigue
• Fixed a case where infected players would get a respawn time on their initial spawn into a map

Server Changes

• Made ms_force_dedicated_server not require cheats
• Add a message when queuing a heartbeat
• Simplified setting of game mode
• Removed convars director_no_human_zombies and director_holdout_mode
• Added mp_gamemode [coop,versus,survival]

General

• Added lobby join and leave messages”

Source: http://store.steampowered.com/news/2433/

Left 4 Dead has been updated with a host of fixes, tweaks and new features, including enhancements to Versus mode for improved competitive play. The full change list is below. For PC users the update will be applied automatically via Steam. Meanwhile, the update will be made available to Xbox 360 players in the coming weeks.

General

* Fixed Survivors being able to climb surfaces marked for versus infected only
* Fixed a class of SurvivorBot bugs dealing with rescuing downed players
* Players can no longer grab ladders while flying through the air after a Tank punch
* Shooting near a car with an alarm that has already fired the alarm will no longer make chirping noises
* Improved loading time
* Fixed mini-gun physics exploit
* Fixed propane tanks (and other physics objects) causing players to fall through elevators
* Fixed rare achievement bug issues
* Fixed several map exploits
* Fixed various match making issues
* Fixed NAT traversal issues

Versus Changes

* Added HUD elements to show status of other infected players
* Changed color of infected player name in chat to red
* Fixed exploit where players could spawn infected bots
* Fixed instance where a Survivor changing to the infected team would be attacked by infected bots
* Normalized special infected melee damage
* Made the following client commands cheat protected: “Kill” and “explode”
* Fixed exploit where infected players could run away and teleport back to gain health
* Players can only change teams once per map
* Players can’t change teams while other players are still loading
* Tank spawns at the same % through the map for both teams in versus mode
* Made the Tank and Witch spawn directly on the escape route
* Increased chance of getting the Tank or Witch
* Fixed team swap issue

Hunter

* Easier to pounce a Survivor who is meleeing
* Increased Minimum damage a Hunter pounce does

Smoker

* Fixed Smoker tongue tolerance
* Smoker now has to be killed or the tongue destroyed for the tongue to break
* Survivors cannot bash someone off the tongue until the Survivor being pulled is paralyzed or hanging
* Tongue attacks that fail to paralyze or hang a Survivor will use the shorter ability delay timer
* Fixed cases where the ability timer was not using the correct time
* Fixed case where you could point at a Survivor but not register a tongue hit
* Fixed Smoker tongue not targeting and landing properly through PZ ghosts
* Smoker tongue does damage every second while dragging paralyzed Survivors

Tank

* Bashable objects now appear with a red glow
* Tanks hitting a car with an alarm disables the alarm permanently
* Tank frustration timer is only reset by hitting Survivors with rocks or fists
* Reduced autoshotgun damage against Tanks

Witch

* Witch spawns at the same % through the map for both teams
* Avoids spawning within a certain % of the tank
* Fixed an exploit where the Witch could be woken up and tricked into attacking Survivors

Source

Story via Ars

Edit: There are rumors cropping up that the Crytek titles Crysis and Crysis: Warhead still maintain their 5 limit SecuROM activation DRM when purchased through Steam.