Doom 3 includes several references to the original Doom:
At the start of the game, the player can access a communal area where there is an arcade machine named Super Turbo Turkey Puncher 3. The game is formed mostly from Doom graphics, and features the fist, status bar face, gibs and a background which is clearly a screenshot from E4M9 of Ultimate Doom. The game logo alludes to Street Fighter Alpha 3 and the fictional developer Nabcon to Capcom.
A texture that was ported from parts of Doom 1 computer textures, is used at several points, mostly used in the CPU banks. It comes mostly from COMP2 and COMPTALL.
Throughout the game, magazines can be found in the Mars base. One of these, GameHOG, features the status bar "ouch face" blown up to fill the front cover, as well as the title of a fictitious game Doom Ultra-XL.
The original cheat codes, when typed at the console, will cause the message "your memory serves you well!" to be displayed telling you that you know your DOOM skills.
The light patterns in the pentagrams found in hell include a small image of the original status bar face. The pentagrams also feature the UAC logo.
In the Monorail level it is possible to witness a picture of a Zombieman. This is possible by activating the noclip cheat and moving to the cinematic area where Betruger transforms a marine. The picture is located on one of the glass panels.