Achievements

Left 4 Dead includes achievements for Steamworks and Xbox LIVE. There are 51 achievements in all for the PC version of Left 4 Dead (not including the 7 from Survival Mode, or the 10 from Crash Course), but only 55 for the Xbox 360 version (not including the 10 from Crash Course); the Outbreak achievement is not in the Xbox 360 version of the game. There are currently 50 achievements for Left 4 Dead 2. In the downloadable campaign, The Passing, 10 new achievements were added to Left 4 Dead 2. The Sacrifice DLC added 5 achievements to both L4D and L4D2.

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 free DLC.

Miscellaneous
Achievements that don't fit anywhere else.