Doom (1993 video game)
Doom (typeset as DOOM in official documents and stylized as DooM in other media) is a 1993 first-person shooter (FPS) video game by id Software. It is considered one of the most significant and influential titles in video game history, for having helped to pioneer the now-ubiquitous first-person shooter. The original game was divided into three nine-level episodes and was distributed via shareware and mail order. The Ultimate Doom, an updated release of the original game featuring a fourth episode, was released in 1995 and sold at retail.
Clone (computing)
Since the existence of video games, clones of successful concepts and brands were common.
For instance, the influential first person shooter Doom lead in 1990s to the creation of a new genre dubbed as Doom clones. In the 2000s the open world action-adventure Grand theft auto inspired the creation of many Grand Theft Auto clones.