A report on List of Doom ports, Doom engine, Hexen: Beyond Heretic and Doom modding

It is also used in Heretic, Hexen: Beyond Heretic, Strife: Quest for the Sigil, Hacx: Twitch 'n Kill, Freedoom, and other games produced by licensees.

The dozens of unofficial Doom source ports that have been created since then allow Doom to run on previously unsupported operating systems and sometimes radically expand the engine's functionality with new features.

Hexen uses a modified version of the Doom engine, which allows looking up and down, network play with up to eight players, and the choice of three character classes.

Hexen is compatible with many Doom source ports; Hexens features are also compatible with Doom WADs made for source ports regardless of what game they are being played on.

On December 23, 1997, id Software released the source code to the Doom engine, initially under a restrictive license.

These engine modifications, or Doom source ports, have since become the target for much of the WAD editing activity, and with the decline of MS-DOS, using a source port became the only feasible way to play Doom for most people.

This is a list of unofficial ports of the engine used to run Doom, referred to as source ports, that expand upon the engine's capabilities, alter how the game being run is played, or make it compatible with other operating systems, and have received substantial notable coverage.

The source port is packaged in the Ubuntu Software Center as well as Fedora's RPM software repository alongside Freedoom.

The source port also supports Heretic, Hexen: Beyond Heretic and Doom II.