Warlords (1980)

Warlords is an arcade game released by Atari, Inc. in 1980. The game resembles a combination of Breakout and Quadrapong (an early Atari arcade game) in the sense that not only can up to 4 players play the game at the same time, but also the "castles" in the four corners of the screen are brick walls that could be broken with a flaming ball.
Warlords uses spinner controllers for player control, and came in both an upright 2 player version and a 4 player cocktail version. The upright version uses a black and white monitor, and reflects the game image onto a mirror, with a backdrop of castles, giving the game a 3D feel. The upright version only supports up to two simultaneous players, which move through the levels as a team. The cocktail version is in color, and supports 1-4 players. 3-4 player games are free-for-all's where the game ends as soon as one player wins. 1-2 player games play identical to the upright version.
According to the Atari video game production numbers, 1014 uprights were made, and 1253 cocktails were produced. The prototype version of Warlords was called "Castles and Kings" and was housed in a 4 player "Sprint 4 like" cabinet - it was huge. Only 2 versions of the prototype were made. The game was considered a success, although the large cabinet made it impossible to produce in large quantities nor was it feasible to install - hence the smaller cocktail design.