Pulsar

Pulsar is a multi-directional shooter arcade game that was released by Sega in 1981, and licensed to Gremlin Industries for US manufacture and distribution (using "Fingers" Malloy, the host of The Snark Factor, on the flyer); it runs on their Vic Dual hardware, and the player must use a four-way joystick to direct a small white tank around changing mazes with a single button to make it fire shots at enemies. The yellow enemies move along the edges of the walls, while the green enemies move randomly and the red enemies bounce off the edges of the walls - and they all move faster, fire faster, and increase in point value, with every round. You should also watch out for "force-field" walls (for they will kill your tank if it gets caught in one); but if you shoot the eponymous "Pulsar", it will explode into six enemies. You will also have to collect the coloured keys to open the numbered locks at the bottom of the maze - and you will receive a double-points bonus if you do it in numerical order, but regardless of whether you opened those locks in numerical order or not, you will always receive a bonus for how much fuel you have left at this point. You will receive extra fuel when you kill enemies and open locks; however, running out will kill you. Your current high-score ranking is also displayed at the bottom of the screen.