Doom (1993 video game)
Because id planned to self-publish the game, as the game neared completion they had to set up the systems to sell the game. Jay Wilbur, who had been brought on as CEO and sole member of the business team, planned the marketing and distribution of "Doom". He felt that the mainstream press was uninterested in the game, and as id would make the most money off of copies they sold directly to customers—up to 85 percent of the planned US$40 price—he decided to leverage the shareware market as much as possible, buying only a single ad in any gaming magazine. Instead, he reached out directly to software retailers, offering them copies of the first "Doom" episode for free, allowing them to charge any price for it, in order to spur customer interest in buying the full game directly from id.
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.