One is a video game released for the Sony PlayStation in 1997. The game was released as a PSone Classic for download on the PlayStation Network on March 18, 2010.
The game is a modern variation of the side-scrolling platform genre. Unlike third-person games such as Tomb Raider, players here primarily move on a 2D plane, but the world is rendered in 3D and the camera will zoom in and out for cinematic effect.
There are six levels in total with a Boss character to face at the end of each; most of whom cannot be dispatched by direct gunfire and instead must be defeated by usage of the surrounding environment.
The goal of One is for the player to discover the identity of the main character John Cain. The only clue available is a barcode on the player-character's neck. At the beginning of the game, John Cain awakens on the floor of an apartment building, with a gun in place of one arm, no memory, and police helicopters shooting missiles through a window. The player is pursued across the city and country-side by military and police forces who are apparently intending to kill Cain. To combat the police and military forces and other enemies, the player has the option to use Cain's newly installed arm cannon, or rely on more traditional fighting weapons like punch and kicking combos.