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 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 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, and Apple's iOS app store. The January 9, 2020 patch added a PC version via the Bethesda.net 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 also included with the GOG versions of Doom and Doom II.

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

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. This also means that certain new features such as freelook are not planned, 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.

Differences in Doom and Doom II
Note that many changes below are carried over from previous Doom Classic revisions.

Ultimate Doom and Doom II

 * 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 (see below).
 * 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:
 * 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 Alex Mayfield (AlexMax).
 * 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.
 * Medikits, stimpacks, and berserk packs were changed to use a green cross instead of a pill.
 * 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:
 * Up: Super shotgun and shotgun
 * Right: Chaingun
 * Down: Rocket launcher
 * Left: Plasma rifle
 * 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

The September 3, 2020 update brought many more changes:
 * Widescreen support, using extended title screens drawn by Stephen Browning (Scuba Steve) (originally created for, but not used in, the WidePix project by Nash Muhandes )
 * DeHackEd support (limited to embedded DEHACKED lumps) written by Simon Howard (Fraggle).
 * Deathmatch 3.0: weapons "stay" after pickup, allowing others to pick them up at the same point, ammo respawn on a 30 seconds timer, invulnerability and invisibility do not respawn.
 * An optional crosshair was added, which also changes color when a valid target is in sight.
 * A secret notification is added, using the sound.
 * A new skill level was introduced, "Ultra-Violence+". It corresponds to UV-fast with multiplayer spawns enabled, bringing in deathmatch weapons and cooperative monsters to the play.
 * Fix to the tutti-frutti error caused by vertically tiling textures shorter than 128 texels.
 * Fix to the timing issue causing the super shotgun to briefly show its muzzle flash after the barrels moved.
 * Fix to the zombieman's firing frame not being lit up.
 * Fix to the Picked up a medikit that you REALLY need! message oversight.
 * Support for Gyro Aim on Switch, PS4, and PC with DualShock4 controllers.
 * Support for MFi, Xbox One, Xbox Series X|S, DualShock4 and DualSense controllers on iOS.

Ultimate Doom specific

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

Doom II specific

 * 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 , 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.

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. The currently active profile must be signed into a Bethesda.net account to download add-ons. Announcements of new add-ons can be found under the News option of the main menu.

Trivia

 * Doom and Doom II originally shipped with a much criticized Bethesda.net 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 update which uses recordings of the music played through a . Later, the  update brought back direct MUS and MIDI playback, but only for addons.
 * 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. There was also no confirmation when selecting this skill. The nightmare skill was fully restored in the September 2020 update.