DOOM 64 is a stand-alone game in the DOOM franchise, rather than a port of the PC versions as found on many other consoles. Doom 64 features new graphics and a new story.
Gameplay remains the same as in the PC classics, with the same weapons and enemies. DOOM 64 utilizes 3D architecture for levels and 2D sprites for objects as in the previous games. The monster sprites are created from 3D models, which for the most part closely resemble their 3D counterparts. However, monster sprites are scaled slightly too large relative to the player's height.
The game features a spartan but new story following the plot of the older games (as opposed to DOOM 3 which rewrites the story). After the events of DOOM and DOOM II: Hell on Earth, Mars was devastated by nuclear strikes designed to remove all possibility of demon life with radiation. However, the strikes were not completely effective, and a single entity survived. Now, years later, the entity is reviving its dead brethren. As the only survivor of the original disaster (code-named the "DOOM episode" by the military), the Marine from the previous games is called in to finish what he started and eradicate the creatures from Hell.
Quoted from the DOOM 64 manual:
"Your fatigue was enormous, the price for encountering pure evil. Hell was a place no mortal was meant to experience. Stupid military doctors: their tests and treatments, were of little help. In the end, what did it matter - it was all classified and sealed. The nightmares continued. Demons, so many Demons; relentless, pouring through.
The planetary policy was clear. An absolute quarantine was guaranteed by apocalyptic levels of radiation. The empty dark corridors stand motionless, abandoned. The installations sealed.
A long forgotten relay satellite barely executing, decayed by years of bombarding neutrons, activates and sends its final message to Earth. The satellites message was horrific, from the planetary void there came energy signatures unlike anything sampled before.
The classified archives are opened. The military episodes code named "DOOM" were not actually completed. A single entity with vast rejuvenation powers, masked by the extreme radiation levels, escaped detection. In its crippled state, it systematically altered decaying dead carnage back into corrupted living tissue.
The mutations are devastating. The Demons have returned even stronger and more vicious than before. As the only experienced survivor of the DOOM episode, your commission is re-activated. Your assignment is clear: MERCILESS EXTERMINATION."
Enhancements were made to the computer Doom engine for use in DOOM 64, and gameplay elements were altered to increase the sense of fear evoked in the player, making Hell a much more frightening place. Doom's core gameplay, however, remained the same: the exploration of demon-infested corridors, looking for key cards, switches and ultimately the map's exit while surviving deadly traps and ambushes.
Key differences from the computer games in the series include:
- 32 exclusive new levels.
- New, larger sprites for all enemies, items, weapons and projectiles which were texture-filtered when close to the player to prevent pixelation.
- No Commandos, Arch-Viles, Spider Masterminds or Revenants (removed due to the limited storage capacity of Nintendo 64 cartridges).
- All new textures, scrolling skies, artificial room-over-room architecture, and custom scripting.
- Tripwire booby traps, from darts to homing fireballs.
- Eerie synth ambient music tracks (instead of MIDI rock music)
- More ambivalent usage of Satanic imagery (inverted pentagrams, inverted crosses, depictions of sacrifice) than the computer version of Doom with differing usages of horror schemes. This makes the game have more of a Lovecraftian or Quake feel.
- More advanced atmospheric colored lighting and effects.
- Re-designed weapons that act more devastating than previous instalments of the game series (realistic jostling movements when firing the weapons are also present, including being knocked back a few inches from a fired rocket).
All the weapons from the original computer game are present (Fist, Chainsaw, Pistol, Shotgun, Super Shotgun, Chaingun, Rocket Launcher, Plasma Rifle, and BFG 9000), but redrawn with new sprites (the chainsaw was given two blades instead of one, and the shotgun's reloading cock at the handle instead of under the barrel). A new weapon known as the Laser (referenced in-game as "What the !@#% is this!") or the Unmaker has been added. It was first mentioned in the Doom Bible and was planned to be featured in the computer Doom games but never appeared. Its appearance in Doom 64 is its only official appearance, and with the power of three ancient artifacts found in the game it becomes more powerful by shooting three laser beams instead of one.
DOOM 64 features 32 original levels:
Since the release of the Doom source code for the computer games, programmers have created feature-enhanced versions of the computer Doom game in their own source ports. Several fans of DOOM 64 decided to work to convert the game's exclusive content to the computer using jDoom, generally considered the most advanced of the source ports in graphics. The add-on, titled "DOOM 64: Absolution" is available for download and features the new graphics and maps of the Nintendo 64 game. It is a near-perfect re-creation of Doom 64, with new, original content, and an incomplete, discontinued expansion, "The Outcast Levels". Not everything is the same, however. For example, the Unmaker fires, in the PC version, little orange pulses. In the Nintendo 64 original, it fires actual red laser beams that can pierce enemies. This mod appeals to many fans as a way to enjoy DOOM 64 without emulation.
- The music and sound effects were done by Aubrey Hodges, who did the original sound and music for the PlayStation port of Doom two years earlier.
- Midway's original title of the game was "The Absolution", but possibly out of potential fear of players not recognizing the game at face value, opted to change the name to "DOOM 64" ("The Absolution" was reused as the name of the last level of the game).
- Midway wanted to include every demon from the original games, as well as a few extra levels, into the final product, but deadlines and memory constraints of the N64 cartridge made them scrap the levels and keep what few demons off the game (Former Commando, Revenant, Arch-Vile, Spider Mastermind)
- The original DOOM 64 team was working on a potential sequel titled "DOOM Absolution" designed only for two-player deathmatches, not long after the first game was released, but decided to scrap it, possibly due to the DOOM engine looking dated, and players' attention focusing on Quake and other, more modern 3D shooters.