The Sony PlayStation version of Doom is a port of Doom and Doom II by Williams Entertainment. It was released on November 16, 1995, and runs on a modified version of the Doom engine used in the Atari Jaguar port. It features 28 levels from Ultimate Doom, 23 from Doom II and 7 original levels.
The game features a multiplayer mode, but lacks split-screen; two consoles have to be linked together instead. This makes the multiplayer experience truer to the original, but at the expense of accessibility.
John Romero is quoted on the back cover, calling this the "best DOOM yet," and is credited as "Creator of DOOM".
It was followed shortly by a port of Final Doom, reusing the same engine and most custom resources.
The original Doom levels are based on the Jaguar version, and therefore, as with all ports based on this version, the simplifications to the map geometry and texturing versus the PC version are carried over. The maps from Ultimate Doom's Episode 4 and Doom II contain similar, although fewer changes. Overall, this means that the number of unique textures per map is lower than in the PC version. Further examples of simplifications would be the omission of crushers in Ultimate Doom and the reduction of large vertical heights. These changes are done mainly for performance reasons; however, there is still noticeable slowdown in certain levels, particularly when playing on the higher difficulty settings.
As a feature unique to the PSX and Saturn ports, monsters from Doom II appear in Ultimate Doom levels when the game is played on the "Ultra Violence" skill level. Also, megaspheres can be found in the exclusive Ultimate Doom levels MAP29: Twilight Descends, MAP30: Threshold of Pain and MAP57: The Marshes, with the latter additionally featuring a super shotgun.
A tougher type of spectre, the nightmare spectre, has been added. While the regular spectre looks like a partially invisible demon, the nightmare spectre is subtractively blended, and is harder to kill due to having twice the hit points of an ordinary spectre.
The final boss from Doom II is not in the game.
As in the Jaguar port, enemies from Doom do different amounts of damage as compared to their PC counterparts. For example, a Zombieman's pistol shots can inflict up to 24 damage, as opposed to the normal maximum of 15. Some enemies are also referred to in slightly different terminology in the game's manual. Zombiemen, again as an example, are referred to as "former soldiers" rather than "former humans".
This game's version of the revenant is considerably easier to tangle with than its PC counterpart; its running speed is approximately half normal, and is akin to a zombie's or imp's pace. While it only fires homing missiles, the missiles are also slower and easier to avoid.
Differences from PC
- All of the gameplay, texture, and map changes from the Atari Jaguar version have been retained for the original Doom maps. Less significant changes were made to the Thy Flesh Consumed and Doom II maps; however, some of the larger maps were cut from the game.
- Many animations had frames cut, making them seem choppier, one apparent example being rockets fired from the rocket launcher.
- Some maps feature a new animated flaming sky.
- The screen resolution was changed from 320x200 to 256x240, which is stretched to roughly 293x240 via NTSC rasterization. Overscan by contemporary television sets, which is variable in nature, would on average show around 224 lines from the middle of the 240 line area, with an 8:7 pixel aspect ratio. New graphics were made for the menu and intermission backgrounds, fonts, and status bar to fit this resolution. The aspect ratios of in-game geometry and sprites are not consistently adjusted, however: architecture appears considerably flattened relative to its PC appearance, while sprites are scaled differently and appear more faithful.
- The sound effects are different from the PC version, and were later reused in Doom 64.
- The PSX SPU's reverb features are utilized, both for sound effects (mainly in enclosed areas) and soundtrack.
- All weapon sprites have been reduced in size. The super shotgun suffered in particular, and was redrawn for the American and European versions of Final Doom, giving it a "sleeker" appearance.
- Different status bar. The one used in this game has a darker tone (more black rather than gray in the original) and does not feature the listing of the remaining ammo of all types on the right side like the original.
- There is no Nightmare! skill level.
- Different cheat codes.
- Passwords are used for loading; while they store numbers as map level, skill level, health, armor and ammo, the numbers for the latter three tend to be rounded. There is no Memory Card usage.
- Spectres do not "shimmer", but are instead rendered using translucency. This is because the partial invisibility effect is difficult to reproduce using such a renderer.
- Though the back of the box touts a "high framerate," the game in fact runs slower than its PC counterpart by design, targeting a 30 Hz framerate for rendering and 15 Hz game logic. Empirical testing shows few levels are actually capable of reaching the target framerate, most averaging in the 20s, and a few dipping as low as the single digits during intense gameplay. This must be measured against other competing console ports of the time, however, which had in most cases significantly worse framerate issues. Even many contemporary PCs were not guaranteed to run the the DOS version at its full 35 Hz framerate.
- Health bonuses and armor bonuses are worth 2% as opposed to 1% (this change remains in place from the Jaguar version).
New ambient background music for most levels sequenced using the PlayStation SPU's capabilities. Additionally, Red Book CD audio is used for the title, menus, demos, intermission, finales, and for the main section of the secret level, Club Doom. Aubrey Hodges created the soundtrack and reused certain songs (the symphonic rock/metal theme, most noticeably) in Doom 64.
- The disc contains several WAD files. Each map is in its own WAD file, ranging from MAP1.WAD (which contains MAP01) to MAP59.WAD. An additional archive, PSXDOOM.WAD, contains all resources, including several unused ones. This makes it a total of 60 WAD files.
- The WADs use the same LZSS-based compression method as the Jaguar Doom port, however they are little-endian files, contrarily to the Jaguar's big-endian WAD.
- The Doom PLAYPAL is different on multiple points:
- Color values are stored as 16-bit little endian ABGR values (using the most significant bit for alpha and five bits for each color channel).
- Index 0 is transparent in all palettes, and none of the other indices are transparent in any palette. Palette colors differ slightly from PC Doom's.
- There are a total of 20 palettes. The first fourteen are equivalent to Doom's, though the tints are not necessarily identical.
- Palette 14 is used for the invulnerability effect. Since this port uses a hardware renderer which ignores COLORMAPs, invulnerability is handled as a palette flash instead.
- Palette 15 is used for the fire sky. Only the first 37 indices are actually used.
- Palette 16 is quite similar to palette 0, with some odd differences. It is used for interface graphics such as CONNECT, NETERR, LOADING, PAUSE, LEGAL, STATUS, as well as IDCRED2 and WMSCRED2.
- Palette 17 is used for the TITLE and DOOM graphics.
- Palette 18 is used for IDCRED1.
- Palette 19, the last one, is used for WMSCRED1.
- All textures have power-of-two dimensions. When the image itself was not resized to fit the dimensions, the added areas are filled with black (index #255).
- Textures are not composited. Instead, they are placed between T_START and T_END markers.
- The TEXTURE1 lump merely enumerate texture dimensions in sequence. Textures are not identified by their name, instead they are enumerated in the same order as they appear in the WAD. However, each individual texture file already features its dimensions, making the TEXTURE1 lump rather redundant. Textures are not composited from multiple patches.
- Spectres and nightmare spectres are not separate mobj types, but merely demons with some specific flags set. These flags can technically be used with other things as well.
Bitmask Effect Use 001xxxxx 50% transparency (B/2+F/2) Cacodemon on Tenements 011xxxxx 100% additive (B+F) Spectre in the exit room of The Focus 101xxxxx 100% subtractive (B-F) and doubled hit points All nightmare spectres 111xxxxx 25% additive (B+F/4) Usual spectres
- A rocket launcher blast originating from a player's rocket launcher shot does not do any damage to him/herself whenever he/she is facing a corner where the walls are aligned in an angle of 90 degrees. The player must also be facing slightly off the corner's edge and be as close to it as possible. A series of images demonstrating the phenomenon in the Final Doom level Crater can be viewed here:    
- 640K of VRAM is allocated for sprites, wall textures and skies. If this limit is exceeded, then the game will crash and a black screen with the text "TEXTURE CACHE OVERFLOW" will appear. 
- Dramatic memory corruption can be triggered by Lost Souls moving outside the normal boundaries of the levels. Linedefs and sectors in the map will become progressively distorted from their normal layouts until the areas become unrecognizable and eventually the game crashes.
- Harry Teasley interview at Doomworld
- Aubrey Hodges interview at gamescares
- Mapping of flags 32, 64, and 128
- Information about the Doom / Doom II PlayStation port on ClassicDOOM.com
- Harry Teasley interview on Doomworld
|Source code genealogy|
|Based on||Name||Base for|
|Jaguar Doom||Doom for Sony PlayStation||Doom for Sega Saturn|
|Doom II v1.666||Doom 64|
|Final Doom (PlayStation)|
|Williams Entertainment • Midway Games|