First-person shooters are a type of three-dimensional shooter game, featuring a first-person point of view with which the player sees the action through the eyes of the player character. They are unlike third-person shooters which are seen from the back, allowing the gamer to see the character they are controlling. The primary design element is combat, mainly involving firearms. They are also often categorized as being distinct from light gun shooters, a similar genre with a first-person perspective which use light gun peripherals, in contrast to first-person shooters which use conventional input devices for movement. Another key difference is that first-person light-gun shooters like Virtua Cop are often on-rail shooters, whereas first-person shooters like Doom are off-rails and free-roaming.
The first-person shooter may be considered a distinct genre in itself, or a type of shooter game, in turn a subgenre of the wider action game genre. Following the release of the influential Doom in 1993, games in this style were commonly termed "Doom clones";in time this term has largely been replaced by "first-person shooter".Wolfenstein 3D, released in 1992, the year before Doom, is generally credited with inventing the genre, but critics have since identified similar though less advanced games developed as far back as 1973.[5] There is sometimes disagreement regarding exactly what design elements constitute a first-person shooter, for example, Deus Ex or Vampire: The Masquerade – Bloodlines are sometimes considered first-person shooters, but may also be considered role-playing video games as they borrow from this genre extensively. Some commentators may extend the definition obliquely to include combat flight simulators, as opposed to characters on foot.