Doom 64

Doom 64, released March 31, 1997 for the Nintendo 64, is a sequel to Doom II. The game has all new graphics and runs on a modified Doom engine, based on the Sony PlayStation port. Doom 64 was released by Midway, in cooperation with id Software.

The plot focuses on events following the original games in the series. An evil entity known as the Mother Demon has survived and brought back the decaying dead creatures the player once killed. It is up to him, the lone space marine, to stop the legions once again.

The game has not officially been ported to modern platforms, although a faithful fan-made engine recreation exists in the form of Doom64 EX.

Story
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.

Far Away...

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.

The Present...

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.

Gameplay developments
Changes were made to the computer Doom engine for use in Doom 64, and gameplay elements were altered. Doom's core gameplay, however remained the same: the exploration of demon-infested corridors, looking for keycards, 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, created from high-poly rendered models.
 * Bilinear filtering applied to textures and sprites.
 * All new textures, scrolling skies, limited room-over-room architecture and more advanced line triggers.
 * More advanced atmospheric colored lighting and effects, such as parallaxing skies, fog and lightning.
 * New ambient music, composed by Aubrey Hodges.
 * New, higher-quality sound effects (the same as used in the PlayStation version).
 * No status bar. Instead, only the numbers for health, armor and ammo are shown, and even these can be turned off.
 * Scripted events through macros somewhat like Hexen. These include tripwire booby traps such as darts, homing fireball launchers and enemies that appear out of thin air.
 * Camera effects.
 * More ambivalent usage of Satanic imagery (pentagrams, inverted crosses, depictions of sacrifice) than the computer version of Doom with differing usages of horror schemes.
 * No commandos, arch-viles, spiderdemons or revenants (removed due to the limited storage capacity of Nintendo 64 cartridges).
 * A new weapon; the unmaker, a weapon that can increase in power throughout the game.
 * The nightmare imp and Mother Demon were introduced as new monsters.
 * The player's viewpoint is from chest level, rather than eye-level, making all objects and characters appear larger in relation to the player.
 * The super shotgun reloads much quicker, nearly the same reload time as the regular shotgun. This makes it one of the most essential weapons in the game.
 * The hell knight and baron of hell can hurt each other with their projectiles, and infight as a result, contrarily to the PC version where there is a hardcoded exception for them.
 * Certain monsters are rebalanced with new behaviors or attack properties (e.g. such as giving the arachnotron a weaker twin plasma gun instead of a stronger single-barrel one).
 * Blowback effects when firing the weapons, e.g. being knocked back a few inches from firing a rocket.

Weapons
All weapons from Doom II are present (albeit redrawn), along with a new weapon known as the Unmaker or the LaserGun (referenced in-game as "What the !@#%* is this!") 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 (known as "Demon Keys") found in the game, it becomes more powerful by additional beams with each key found.

The Demon Keys are also a means to clear MAP28: The Absolution quicker: Each teleporter in the map has a symbol representing each key behind them and if the player has the right key, the corresponding teleporter is disabled.

Levels
Doom 64 featured 32 original levels: One additional special map, MAP33: Title, is used in the introductory cinematic and is not accessible for normal play.

Enemies
Doom 64 includes the following monsters from Doom and Doom II: Doom 64 also has new monsters, which are:
 * Arachnotron
 * Baron of hell
 * Cacodemon
 * Cyberdemon
 * Demon
 * Hell knight
 * Imp
 * Lost soul
 * Mancubus
 * Pain elemental
 * Shotgun guy
 * Spectre
 * Zombieman
 * Mother Demon
 * Nightmare Imp
 * Marine bots, which only appear in the title map.

Other versions
There has never been an official port of Doom 64 to any other platform, and the likelihood of this ever occurring is poor due to the bankruptcy of as of February, 2009.

Several fans of Doom 64 decided to work to convert the game's exclusive content to the computer using the Doomsday engine. This stand-alone mod, built on the 1.7.14 release of Doomsday, titled Doom 64: Absolution, was released in 2003. It included faithful albeit limited recreations of the original Doom 64 levels and monsters along with several unique new maps. It appealed to many fans as a way to play through the game on a computer without using emulation.

Samuel "Kaiser" Villarreal, the lead developer of the Absolution total conversion, would later create Doom64 EX, an actual source port for the original game data as extracted from the ROM.