The CD contains 20 WAD files created by various authors under contract. The file TEETH.WAD contains a secret level, so there are a total of 21 levels. As a bonus, 1,830 amateur custom PWAD files downloaded from the Internet (collectively called Maximum Doom) and a Master Levels for Doom II poster are included. Version 5.9c of the Doom-It tool, created by Chris Badger, is included as well. Also of note is that some of the contracted designers for the Master Levels had levels they had previously released on the Internet that were included in Maximum Doom.