RawSteelUT: Just out of curiosity, what was censored out of the games, other than the Nazi imagery in Doom 2 (and I believe the removal of a secret level)? And was Doom 3 itself edited in any way, other than additional enemies? I've played both versions of D3 all the way through (PC version of classic and PS3 version of BFG), and didn't notice anything different aside from enemy placement and population.
Doom 2
-In the two secret levels the SS enemies are replaced with zombiemen and all Wolfenstein wall textures are replaced.
-Medical kits are replaced with a heart instead of a cross. While I dislike this change I can understand it and it doesn't bother me as much as other acts of censorship. Basically the Red Cross is angry at the use of crosses in violent games... despite 'health kits' in games being a good thing for the player. Despite the stupidity of their complaint they do good things in the world and if they threaten legal action... well what can you do.
Doom 3
-Doom 3 does NOT have additional enemies. I'd actually like that to make up for their other changes.
-Game is brightened up a bit. Hurts atmosphere.
-The flashlight is no longer a separate 'weapon' that you switch to and is instead a suit light. The flashlight was an important GAMEPLAY MECHANIC. It was a constant mental decision throughout the game... improve your ability to see at the cost of extremely limited defense and a time to switch back to a better weapon vs. keeping a weapon out but having trouble seeing the enemies.
-The player moves faster. Doom 3 is supposed to be a slower atmospheric horror experience.
-Ammunition pick ups give drastically more ammo. Playing through the original versions you could actually run out of ammo with certain weapons and need to change. Short of standing around wasting ammo you will never run out for any of the guns. If they actually had added more enemies to the campaign it might have made up for this mess.
Doom 3: Resurrection of Evil
Most of the issues above in Doom 3 weren't really 'censorship'. Now with RoE we get into real censorship.
-RoE added many new arcade machines to the game. I believe about 3 of them, from a game where you pop a balloon with a shotgun, a pong like game and another where you shoot asteroids. ALL of them were removed and replaced with Super Turbo Turkey Puncher. I have no idea why. Maybe they were worried about a lawsuit as all of the arcade games I mentioned were takes on classic arcade games.
-There is a section later in the game where you acquire a hazmat suit and must navigate a toxic sewer. This was an obvious throwback to the Hazmat suit of the classics. The section was a bit challenging as you had an oxygen meter you have to refill with canisters, similar to when you go on the surface of mars. The hazmat suit is now completely removed and you just go through the section normally.
There are other changes in the games that escape me at the moment, as these were the ones that bugged me the most.
Random fact: The original XBOX version of Resurrection of Evil also changed the flashlight mechanic. Instead of the flashlight being a separate 'weapon' it instead is attached to the pistol. This still meant the player was trading superior firepower for visibility. So in the various releases of Doom 3 and expansion the series has had THREE separate takes on the flashlight: infinite battery carryable weapon, infinite battery attached to pistol and attached to suit but with a battery that runs out and charges once turned off.