Duke Nukem 3D

Duke Nukem 3D is a first person shooter developed by 3D Realms and released by  Apogee in 1996. The story features the protagonist Duke Nukem fighting against an alien race. It contained many of the same features as Doom, although the atmosphere of the game is different: Duke Nukem contains lots of "one liner" humour and features partial female nudity.

Technical
While Doom and Duke Nukem 3D feature similar technology, Duke Nukem 3D could in some respects be considered technically superior. The rendering engine features slopes, overlapping and moving sectors, arbitrary scaling of textures and strong scripting capabilities. All of the game behavior is stored in external text files which can be modified to change almost any feature of the game. The registered version of the game came with an editor, "Build", which included a 3D editor mode. It is often considered the most simple editor ever made.

Similarities
Many of the monsters and other features in Duke Nukem are analogous to similar concepts in Doom. The following is a list of analogies that describe the similarities between Doom and Duke Nukem 3D (and other Duke Nukem games).

Trivia

 * A reference to Doom is included in Duke Nukem 3D. E1L3 contains a church. Standing in front of the cross at the front of the church, there is a switch.  Pressing this gives a red tint to the room while the horizontal bar of the cross lowers until it appears to be fully inverted.  Smashing the left stained glass window reveals a secret passageway, that may contain an Octobrain.  Walking down the passageway, a dead Doom marine can be seen. Duke says, ”That’s one doomed space marine”. Caleb, the hero of Blood sees also Duke crippled and shakes him. (This secret area was removed from later releases, possibly due to legal reasons.)


 * Another reference could be found in the Sunsoft's unofficial Duke3D add-on "Nuclear Winter". In one area of the level "Land of Forgotten Toys" Duke is teleported to a parody of Doom's E1M1, complete with a sign reading "This Building Condemned". The player cannot access any other rooms with the exception of jumping out the windows next to the armor pedestal, where an important yellow card, a teleporter back to the rest of the level, and of course some dead Doom marines can be found.


 * A special utility to convert Doom-based WAD files into a format playable by the Build engine, WAD2MAP, was included on the Duke Nukem 3D: Atomic Edition CD. The program itself is currently available on various websites.


 * The Doom II megawad, Memento Mori II, released six months after Duke Nukem 3D, contains some references to this game. The first appears in the mission briefing for MAP04: Ratamahatta, in the form of an ill-fated scout named "Duck Nukem."  The second, and more famous one, is in the level itself, where the player eventually arrives at Duck Nukem's grave.  The last is in the mission briefing for MAP18: Regulate, featuring an equally ill-fated scout named "Ken BUILDerman," whose name is a reference to Ken Silverman, programmer of the Build engine.