Doom (1993 video game)
The ability for others to create custom levels and otherwise modify the game using WAD files turned out to be a popular aspect of "Doom". Gaining the first large mod-making community, "Doom" affected the culture surrounding first-person shooters, and also the industry. Several future professional game designers started their careers making "Doom" WADs as a hobby, among them Tim Willits, who later became the lead designer at id Software.
Development of Doom
Over spring and summer of 1993, Carmack worked on improving the graphics engine of the game. After Romero's level designs started to cause problems with the engine, he researched and began to use binary space partitioning to quickly select the portion of a level that the player could see at any given time. Additionally, in March 1993, the company had to stop work on the game while the team spent three weeks building a Super Nintendo Entertainment System port of "Wolfenstein 3D", after the contractor who had agreed to do the port proved to have made no progress. Taylor, along with programming other features into the game, added cheat codes; some, such as 'idspispopd', were based on ideas their fans had come up with while eagerly awaiting the game. By fall, the game was nearing completion, with players eager to see it, spurred on by a leaked press demo. John Carmack began to work on the multiplayer component of the game; within two weeks he had two computers playing the same game over the internal office network. Soon, the office was playing four-player Deathmatch games.