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.
First-person shooter
"Doom", released as shareware in 1993, refined "Wolfenstein 3D's" template by adding improved textures, variations in height (e.g., stairs the player's character could climb) and effects such as flickering lights and patches of total darkness, creating a more believable 3D environment than "Wolfenstein 3D's" more monotonous and simplistic levels. "Doom" allowed competitive matches between multiple players, termed "deathmatches," and the game was responsible for the word's subsequent entry into the video gaming lexicon. According to creator John Romero, the game's deathmatch concept was inspired by the competitive multiplayer of fighting games. "Doom" became so popular that its multiplayer features began to cause problems for companies whose networks were used to play the game.