Doom Classic Unity port


The Doom Classic Unity port is a series of official ports of Doom and Doom II initially developed by Nerve Software in cooperation with id Software and first published by Bethesda on July 26, 2019 as part of the "Year of Doom" promotional campaign. It was initially announced on stage during the QuakeCon 2019 (DoomCon) keynote presentation. The port is based on the Doom Classic codebase, but replaces the id Tech 4 shell with one based on the Unity game engine. This offers immediate portability to a wide array of targets - the Doom and Doom II ports were available at initial launch for the Sony PlayStation 4, Nintendo Switch, Microsoft Xbox One, the Google Play app store for Android, and Apple's iOS app store. The January 9, 2020 patch added a PC version via the distribution platform. This was also extended to the Steam distribution platform by the September 3, 2020 update. As of August 17, 2022, it is now included with the GOG versions of Doom and Doom II,[1] and as of August 18, it has also been released on the Epic Games Store. In May 2023 it was added to PlayStation Plus Premium.


Although utilizing the Unity engine, this is a true Doom engine port, not a Unity recreation. Unity is merely used as a shell—more formally referred to as an abstraction layer—for handling input and output, while rendering is still performed by the original Doom engine.[2] The actual Doom game code is contained in a DLL which is loaded by the Unity framework to run the game; this allows simplified portability.[3]

Static limits are raised and engine bugs are fixed on a case-by-case basis, as required to support the additional features introduced in the port without breaking demo compatibility.[4] This also means that certain new features such as freelook are not planned,[5] and that certain limitations of the original engine, such as the issues when attempting to load sprites, flats, and textures from different archives, are left in place.[6]

Differences in Doom and Doom II[edit]

Note that many changes below are carried over from previous Doom Classic revisions.

Ultimate Doom and Doom II[edit]

  • Local multiplayer is available.
  • Cheat codes are available and accessible via the Options menu.
  • The pickup sprites for the stimpack, medikit, and berserk (STIMA0, MEDIA0, PSTRA0) are modified in compliance with the Red Cross' wish that its symbol not be used in games. Initially the pill graphics from previous Doom Classic versions were reused. This was later changed in the January 9, 2020 update to a green cross.
  • Originally, the DMENUPIC that was the title screen in the original Xbox 360 version is used here. As of the September 2020 update, the TITLEPIC and CREDIT lumps screens are shown again, modified for 16:9.
  • New to the port is the addition of creative credits that resemble the ending credit sequence of Doom (2016), where various levels and battles are shown briefly while the camera pans around and showing the names of Nerve Software key staff. Doom and Doom II each have their own sequences, and after the montage ends, the staff credits roll will begin.
  • Music tracks do not loop seamlessly due to the nature of them being a recording.
  • The automap shows the kills, items, and secrets statistics during the game, using small icons of a skull for kills, a health bonus for items, and a green interrogation mark for secrets.

Significant changes and additions were made in the update released on January 9, 2020:[7]

  • Renderer framerate increased to 60 Hz (It was later updated for 120Hz and above with options to cap it at 30, 60 and 120 frames a second), with an interpolation system written by Lexi Mayfield (LexiMax).
  • An add-on system was integrated. The initial batch of supported add-ons were SIGIL, No Rest for the Living, TNT: Evilution, and The Plutonia Experiment. The Android and PC versions support addition of custom add-ons by the end user.
  • Support for aspect ratio correction was added.
  • Support for quick save and load were added.
  • A level select menu was added, allowing the game to be started on any level at any skill.
  • A weapon carousel was added, allowing instant selection of weapons without cycling through every intermediate weapon and waiting on the resulting raise and lower animations.
  • Quick weapon swap via the directional pad was added, with the following control assignments:
  • Overall brightness and level brightness controls were added.
  • Random sound effect pitch can now be toggled on or off.
  • The split screen HUD for multiplayer was minimized, removing the status bar to allow more game display space.

The March 31, 2020 update fixed the remaining audio issues (sounds with a 22050 Hz sample rate were played incorrectly at 11025 Hz) and added No End In Sight to the list of official add-ons[8]

The September 3, 2020 update brought many more changes:[9]

Ultimate Doom specific[edit]

  • All animation from the intermission screens has been restored; they were originally missing from BFG Edition's Doom Classic.
  • The NIN logo on E4M1: Hell Beneath has been removed, presumably to avoid trademark infringement.

Doom II specific[edit]

  • BFG Edition's MAP31: IDKFA and MAP32: Keen has been reverted back to MAP31: Wolfenstein and MAP32: Grosse alongside their respective map music, D_EVIL and D_ULTIMA.
  • The ZWOLF* texture with Nazi iconography (Hitler portraits, swastikas, Reichsadlers, etc.) have been censored. These were initially identical to the versions that appeared in BFG Edition, but have been edited in the January 9, 2020 patch to be closer to the original textures. The BFG Edition versions of textures which had Nazi detailing were the same as undetailed versions of those wall textures. As of the patch, they have instead been restored to the original versions and then edited, replacing swastikas with the triangle logo used in the German version of Wolfenstein: The New Order, while Hitler has lost his toothbrush mustache, making him resemble the Staatmeister from the Super Nintendo version of Wolfenstein 3D. The definitions in TEXTURE1 are identical; it is the patches that have been changed.
  • The Wolfenstein SS (which were effectively removed in BFG Edition) have been restored. As of the January 9 patch, the second half of their sight sound has been redubbed - they now say "schutzkämpfer" instead of "schutzstaffel", the first half still using John Romero's voice while the other half was re-recorded by Mike Rubits of id Software. Their death sounds are as normal.
  • MAP06: The Crusher has been edited to remove the linedef actions on the door track of the red key door which would crash the game.
  • MAP33: Betray (Xbox Doom II), which was previously featured (albeit inaccessible) in the Xbox 360 port of Doom II and the Doom 3: BFG Edition version, is completely omitted in the Unity port and the 2019 Doom II re-release.


The add-ons menu on Xbox One.
Main article: Official add-ons

Unlike many home console ports, this one allows community created content to be loaded. There is a curated selection of add-ons available for both games on home consoles and iOS. On the PC and Android platforms, users can add to this list themselves by copying files to the add-ons folder. DeHackEd mods need to be merged into PWADs in order to be played properly. The currently active profile must be signed into a account to download add-ons. Announcements of new add-ons can be found under the News option of the main menu.


  • Doom and Doom II originally shipped with a much criticized login screen upon startup (for the purposes of rewards via the Slayers Club), which was made less intrusive in a later update.
  • The music originally played recordings of original songs at a noticeable reduced tempo and with inaccurate sound font voices. This was later rectified with the September 27, 2019 update which uses recordings of the music played through a Roland SC-55. Later, the January 9th, 2020 update brought back direct MUS and MIDI playback, but only for addons.[7]
  • On Nightmare!, the fast monsters mechanic was originally removed entirely: fireballs shot by imps, cacodemons, barons of Hell and Hell knights were no longer sped up, and neither was the running speed of demons. Monsters retained increased reaction times.[12][13] There was also no confirmation when selecting this skill. The nightmare skill was fully restored in the September 2020 update.

See also[edit]


  1. (17 August 2022). "The wait is over - DOOM & DOOM II updates featuring enhanced, as well as classic versions, are now available on GOG! 😈🎮." Twitter. Retrieved 17 August 2022.
  2. Mike Rubits (sponge) (3 July 2020). opinions on the newer doom ports on xbox one, ps4, nintendo switch. Doomworld forums. Retrieved 13 September 2020.
  3. Mike Rubits (sponge) (3 July 2020). The Unity Port Thread - PS4/Xbox One/Switch/IOS/Android. Doomworld forums. Retrieved 13 September 2020.
  4. Mike Rubits (sponge) (5 September 2020). The Unity Port Thread - PS4/Xbox One/Switch/IOS/Android. Doomworld forums. Retrieved 13 September 2020.
  5. Mike Rubits (sponge) (10 March 2020). The Unity Port Thread - PS4/Xbox One/Switch/IOS/Android. Doomworld forums. Retrieved 13 September 2020.
  6. Mike Rubits (sponge) (5 September 2020). The Unity Port Thread - PS4/Xbox One/Switch/IOS/Android. Doomworld forums. Retrieved 13 September 2020.
  7. 7.0 7.1 tokyopunchout (9 January 2020). "DOOM & DOOM II Patch Notes." Community Forums. Retrieved 9 January 2020.
  8. tokyopunchout (31 March 2020). "DOOM & DOOM II Patch Notes." Community Forums. Retrieved 31 March 2020.
  9. Manny Pérez (3 September 2020). "DOOM & DOOM II Update - September 3." Slayers Club (archived 🏛). Retrieved 3 September 2020.
  10. Parker Wilhem (18 September 2020). "Enjoy expanded widescreen art from our re-releases of DOOM (1993) & DOOM II!" Slayers Club (archived 🏛). Retrieved 22 September 2020.
  11. Scuba Steve (3 September 2020). WidePix: 16:9/21:9 Graphics Replacement Project. ZDoom forums. Retrieved 3 September 2020.
  12. id Software (23 July 2005). "Doom source release." GitHub. Retrieved 7 March 2020.
  13. id Software (26 November 2012). "Doom 3: BFG Edition source code." GitHub. Retrieved 7 March 2020.

Games in the Doom series
Classic Doom
Doom 3 Doom 3Doom 3: BFG EditionDoom 3: VR Edition

Expansions: Doom 3: Resurrection of EvilThe Lost Mission

Official ports: Doom 3 (2019 version)

Related: id Tech 4

Doom (2016) Doom (2016)Doom VFRDoom Eternal

Related: Development of Doom (2016)id Tech 6id Tech 7

Mobile games Doom RPGDoom II RPGDoom ResurrectionMighty Doom
Canceled games Doom AbsolutionDoom 4 1.0
Tabletop Doom: The BoardgameDoom: The Board GameAssault on Armaros Station
Related: Commercial gamesExpanded universeList of booksList of commercial compilations
Source code genealogy
Based on Name Base for
Doom Classic Doom Classic (Unity) None