Eliminator1981

This 1981 vector graphics arcade game is available in both two- and four-player configurations.

A top-down space shooter set within a bounded playfield, where the player maneuvers a ship using rotation, thrust and forward-firing controls (much like Asteroids or Space War). Each stage is populated by autmated drone ships (or by competing players), and dominated by the titular enemy: a moving, rotating space fortress surrounded by a lethal force field.