very popular. The idea of creating a first-person shooter in the Star Wars universe was inspired by fan mods of Doom which had levels set on the Death Star. The developers of Dark Forces wanted to adapt the FPS format into an adventure game. To do this they introduced puzzles and strategy, along with a Star Wars plot. Originally Luke Skywalker was intended to be the main character in the game, however the developers realized that this would add constraints to gameplay and storyline. Instead a new character, Kyle Katarn, was created. Upon release, Dark Forces was commonly called a "Doom clone", but the game makes significant expansions upon the gameplay features present in Doom. New gameplay mechanisms that were not common at the time of release include the ability to look up and down, duck, jump, and swim. The use of multiple floor levels is another technical advance in the first-person shooter genre. To produce these new features, the developers wrote a game engine from scratch. The Jedi game engine can create gameplay and graphical elements such as fully 3D objects, atmospheric effects such as fog and haze, animated textures and shading. Stinnett indicated that the developers wanted these elements to be part of an "active environment," and features were included to create this: "ships come and go at the flight decks, rivers sweep along, platforms and conveyor belts move and much of the machinery functions." The Dark Troopers in Dark Forces were created specifically for the game by Justin Chin and Paul Mica. Chin notes that they were designed as a more advanced enemy when compared to standard stormtroopers: "Instead of just beefing up the stormtroopers, I designed them to be more efficient. I wanted something more terrifying and more omnipotent." Three designs for the Dark Troopers were produced for Dark Forces. Lucasfilm licensing department initially rejected two of the designs for looking too much out of character, so Chin produced new designs which were ultimately approved. The development team collaborated with staff at Skywalker Ranch for the sounds, music, and costumes used in the cutscenes. Dark Forces was ported from DOS to Apple Macintosh. This presented several challenges for the developers. LucasArts requested the game to be produced for both DOS and Macintosh with the same system requirements, specifically the random-access memory (RAM). The Mac OS runs a graphical user interface which uses up RAM while DOS