Gun Game is a game mode where you work your way through a series of weapons by scoring kills. Players usually start with a smaller weapon, like a handgun, and once a player scores a kill, they are immediately upgraded to a different gun. If a player is killed by a knife, they are demoted one weapon tier. The first player to work their way through all the weapons wins the match.
After originating in early Counter-Strike PC games, it has since been introduced into the Call of Duty and Battlefield franchises.