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.
Doom (1993 video game)
The team agreed to pursue the "Doom" concept, and development began in November 1992. The initial development team was composed of five people: programmers John Carmack and Romero, artists Adrian Carmack and Kevin Cloud, and designer Hall. They moved offices to a dark office building, which they named "Suite 666", and drew inspiration from the noises coming from the dentist's office next door. They also decided to cut ties with Apogee Software, their previous publisher, and to instead self-publish "Doom".