Spacewar! is a space combat video game developed in 1962 by Steve Russell in collaboration with Martin Graetz, Wayne Wiitanen, Bob Saunders, Steve Piner, and others. It was written for the newly installed DEC PDP-1 minicomputer at the Massachusetts Institute of Technology. After its initial creation, Spacewar! was expanded further by other students and employees of universities in the area, including Dan Edwards and Peter Samson. It was also spread to many of the few dozen installations of the PDP-1 computer, making Spacewar! the first known video game to be played at multiple computer installations.
The game features two spaceships, "the needle" and "the wedge", engaged in a dogfight while maneuvering in the gravity well of a star. Both ships are controlled by human players. Each ship has limited weaponry and fuel for maneuvering, and the ships remain in motion even when the player is not accelerating. Flying near the star to provide a gravity assist was a common tactic. Ships are destroyed when they collide with a torpedo, the star, or each other. At any time, the player can engage a hyperspace feature to move to a new and random location on the screen, though in some versions each use has an increasing chance of destroying the ship instead. The game was initially controlled with switches on the PDP-1, though Bob Saunders built an early gamepad to reduce the difficulty and awkwardness of controlling the game.
Spacewar! is one of the most important and influential games in the early history of video games. It was extremely popular in the small programming community in the 1960s and the public domain code was widely ported and recreated at other computer systems at the time, especially after computer systems with monitors became more widespread towards the end of the decade. It has also been recreated in more modern programming languages for PDP-1 emulators. It directly inspired many other electronic games, such as the first commercial arcade video games, Galaxy Game and Computer Space (1971), and later games such as Asteroids (1979). In 2007, Spacewar! was named to a list of the ten most important video games of all time, which formed the start of the game canon at the Library of Congress.