Total conversion

A total conversion (TC) or Megawad is a PWAD that replaces all or almost all of the resources used within the original game. The first total conversion was Aliens TC, developed by Justin Fisher and released on November 3rd, 1994. Other well-known examples of total conversions include Batman Doom, Hacx: Twitch 'n Kill, and Action Doom.

Freedoom is not a total conversion as the project intends to be a standalone IWAD compatible with any source-port.