The idea of Doom started in September of 1992, right after Spear of Destiny was shipped. John Carmack, who came up with the name 'Doom' after watching a movie (The color of money) where Tom Cruise shows up at a pool hall with a custom pool cue in a case. "What do you have in there?" someone asks. "Doom." Cruise replied. He started making the engine while the rest of id worked on Spear of Destiny, which was later used instead for Shadowcaster. This engine was basically his initial research into coming up with the DOOM engine. Said Carmack. The game was originally the game for the Aliens movie but that idea was scraped at the last minute because id wanted total creative control. Carmack said that instead of aliens we should use hellspawn.

Ultimate Doom is the original 3 episodes of Doom with an extra one 'Thy Flesh Consumed'. (Published in 1995 by GT Interactive)
On December 10, 1993, id released its much-anticipated DOOM. DOOM attained phenomenal success and is still recognized as the hottest 3-D action game of all time. DOOM changed the face of computer gaming forever. Recognized as the catalyst and inspiration of what we know now as 3-D action gaming, an estimated 15 million copies have been downloaded around the world, passed from player to player by floppy disk or online networks. In 1994, DOOM was awarded Game of the Year by both PC Gamer and Computer Gaming World and received the Award for Technical Excellence from PC Magazine.
Doom was originally going to have bullet holes in walls and visible monster damage, but were scraped because it would use up too much memory on older computers.A hub system like in hexen was going to be used too but taken out because it was too much to accomplish at that early of a date with the time frame they were aiming at. The knife, bayonet, machine gun, Unmaker and Dark Claw. Anything else you might see in the design doc was not seriously considered; they were weapons that would have made it in if there was enough time and the balance would work out.
The BFG was changed because 8,000,000,000 fireballs (1) looked like Christmas and (2) slowed the engine down on a 386/33 because there were too many sprites on the screen. Additionally, it was cooler the way it turned out because it didn't look like we just modified the Plasma gun to make a more powerful weapon.

Doom II is the successor to Doom. It was released on December 10, 1994. The really noticeable difference with Doom is the level design, one new weapon (the super shotgun) and a bunch of new monsters: Chaingun guy, Hell Knight, Arachnotron, Pain Elemental, Revenant, Mancubus and the Arch Vile.
And, of course, higher system requirements - due to more complex levels and larger packs of monsters.

Final Doom is the last in the Doom games. It was made not by id Software but by TeamTNT who also made the Boom engine, an add-on made with the recently released source code. It contains two new 32 level doom2 wads called 'Evilution' and 'The Plutonia Experiment', heaps of new music and some new textures.

Final Doom is the last in the Doom games. It was made not by id software but by TeamTNT who also made the Boom engine, an add-on made with the recently released source code. It contains two new 32 level doom2 wads called 'Evilution' and 'The Plutonia Experiment', heaps of new music and some new textures.