Video game clone grouped as "Myst clones". Some video game genres are founded by archetypal games of which all subsequent similar games are considered derivatives; notably, early first-person shooters were often called ""Doom" clones", while the success of the open-world formula in "Grand Theft Auto" led to the genre of GTA clones. The genre of endless runners is based on the success and simplicity of the game "Canabalt". In these cases, games that are "clones" of another are generally not implied to have committed any intellectual property infractions, and otherwise considered legally acceptable practices, although calling such games clones is generally considered derogatory.
NFL GameDay (video game series) is also the first football video game to feature 3D polygonal graphics. "NFL GameDay 99" is the fourth game in the "NFL GameDay" series. It was released July 31, 1998 on the PlayStation, and August 31, 1998 on the PC, both by 989 Sports. On the cover is Terrell Davis. "NFL GameDay 2000" is the fifth video game in the "NFL GameDay" series. It was released July 31, 1999 on the PlayStation by 989 Sports. On the cover is Terrell Davis. "NFL GameDay 2001" is the sixth video game in the "NFL GameDay" series, and the first to be released