Hall was upset with the reception to his designs and how little impact he was having as the lead designer. He was also upset with how much he was having to fight with John Carmack in order to get what he saw as obvious gameplay improvements, such as flying enemies, and began to spend less time at work. In July the other founders of id fired Hall, who went to work for Apogee. He was replaced in September, ten weeks before the game was released, by game designer Sandy Petersen. The team also added a third programmer, Dave Taylor. Petersen and Romero designed the rest of "Doom"s levels with different aims: the team believed that Petersen's designs were more technically interesting and varied, while Romero's were more aesthetically interesting. In late 1993, after the multiplayer component was coded, the development team began playing four-player multiplayer games matches, which Romero termed "deathmatch". According to Romero, the game's deathmatch mode was inspired by fighting games such as "", "Fatal Fury", and "Art of Fighting".