Mod

A video game mod in Left 4 Dead and Left 4 Dead 2 allow players to modify their gameplay, with either cosmetic changes, custom campaigns and mutations, scripts or mod that help the game easier (or more challenging) for them as a few. In the wiki, it can refer to:


 * Steam Workshop - A platform that allow players to upload and download mods from other players for Left 4 Dead 2.
 * Custom Campaigns - Campaigns that was made by the community to be played by other players.
 * Featured Campaigns - Custom Campaigns that was featured by Valve on the blog page and hosted on official servers due to their outstanding quality.