Achievements

Left 4 Dead includes achievements for Steamworks and Xbox LIVE. There are 73 achievements in all for the PC version of Left 4 Dead, but only 65 for the Xbox 360 version; the Outbreak achievement is not in the Xbox 360 version of the game and Survival Pack on Xbox 360 adds no new achievement due to technically being only a patch, not a DLC. There are currently 69 achievements for the PC version of Left 4 Dead 2 (one of which can no longer be earned) and 66 achievements for the Xbox 360 version.


 * Survival Pack adds 7 new achievements to Left 4 Dead for the PC version only.
 * Crash Course adds 10 new achievements to Left 4 Dead.
 * The Passing adds 10 new achievements to Left 4 Dead 2.
 * The Sacrifice adds 5 new achievements to both Left 4 Dead and Left 4 Dead 2, and for the Xbox 360 and PC as well as Mac.
 * The Cold Stream update currently adds 2 new achievements to Left 4 Dead 2 called Stream Crosser and Connecting Fight, although the latter achievement is actually keyed to the conversion of the Dead Air campaign in Left 4 Dead 2. As a reward for 60,000 players earning the Connecting Fight achievement, Valve released the beta version of the Blood Harvest campaign for Left 4 Dead 2.
 * A special holiday-themed achievement, called Valve Gift Grab 2011 - L4D2, was added to the PC version of Left 4 Dead 2 for a limited time in late December 2011.
 * The achievement Good Guy Nick tells you to survive a campaign with free weekend players

Note: Since the Crash Course update, achievements cannot be earned with cheats turned on (sv_cheats = 1). However, one way is to play on Versus mode with everyone helping each other to get achievements.

Survival Mode
None of the Survival Achievements are present in the Xbox 360 version of the game since it is a free DLC.

Miscellaneous
Achievements that don't fit anywhere else.