Galaga is a 1981 fixed shooter arcade video game developed and published by Namco. In North America, it was released by Midway Manufacturing. It is the sequel to Galaxian (1979), Namco's first major video game hit in arcades. Controlling a starship, the player is tasked with destroying the Galaga forces in each stage while avoiding enemies and projectiles. Some enemies can capture a player's ship via a tractor beam, which can be rescued to transform the player into a "dual fighter" with additional firepower.

Shoot 'em ups are a sub-genre of action games. There is no consensus as to which design elements compose a shoot 'em up; some restrict the definition to games featuring spacecraft and certain types of character movement, while others allow a broader definition including characters on foot and a variety of perspectives.