Custom Campaigns

Custom Campaigns, also known as Community Campaigns, are community-created campaigns that can range in size from a full campaign, to a single chapter. Some custom maps are specifically designed for game modes like Scavenge and Survival. Custom content can only be created and used by PC users. Xbox 360 players are unable to use custom content due to technical and financial difficulties regarding porting community-based content over.

Valve is supportive of custom content. They have a SDK for each of their games including Left 4 Dead and Left 4 Dead 2, which allows for easy creating and installing of custom campaigns. They have also released audio recordings by the voice actors of the Survivors for use in specific custom campaigns and feature some custom campaigns on their online blog, as well as uploading specific custom campaigns onto the official servers for more accessibility.

The custom campaign cannot be played on official servers. But can be played on Best server or Local server.

After the February 7, 2013 update. Steam introduced the Steam Workshop where users can upload their custom created maps or content. The contents can be downloaded by subscribing a custom content. Without need to install the addons manually. Furthermore if the same account is logged on different PC, the mods is retained there as well. Internet connection is required however.

How To Install
Once a custom campaign is downloaded from a site, the VPK file is simply placed into the addons folder found in either Left 4 Dead or Left 4 Dead 2 folders. Campaigns are generally created for a certain game; a campaign created for Left 4 Dead may not always work for Left 4 Dead 2, and vice versa, so be aware which game the custom campaign is for before installing.

Some custom campaigns may not be encased in a single VPK (that could be opened with GCFScape;) the file may be a zip or rar file containing a number of .bsp (that could be decompiled to a .vmf file using BSPSource) and .nav files as well. In this case, the file will generally have instructions on where to place them, but usually, the .bsp and .nav files, along with related .txt files, will be placed in the maps folder.

With the updates of Steam Workshop. Any campaigns that were uploaded on the Workshop can be downloaded by clicking the "subscribe" button. Some campaigns are either packaged in one content, or split in parts (due to workshop max file size limits) where all parts must be subscribed in order to play. After subscribing, the workshop content will start download and ready to play.

List of Full-Length Custom Campaigns
Here is a list of custom campaigns which have been noted by their creators to be 'complete', or at least in the final build, with no major updates planned unless concerning bug fixes. These are based around Campaign mode, with the length and number of maps being roughly comparable to standard canon Campaigns. There may be optional modes within the maps catering to Versus, Scavenge and Survival. Descriptions are taken from where the map is found, unless no description was given.