Slither

Slither is a multi-directional shooter arcade game, that was released by GDI and Century 11 in 1982; it runs on its own dedicated hardware (two Motorola M6809s running at 1.33125 MHz with two Texas Instruments SN-76496s at the same speed for its sound), and was later ported to the ColecoVision in 1983. The player must use a track-ball to direct a "Blaster" ship (like that of Atari's Centipede) around the screen, and the game begins with only a few snakes present (as that bonus score counts down) - and, once you have killed all of the snakes, you will receive the remaining amount of bonus points, as additional snakes begin to attack in waves. Each time the bonus score counts down to 0, snakes of a different colour will appear; pterodactyls and gorillas will also appear to create two additional dangers (the latter also to place additional grass on the screen, and if they touch the snakes, they will become invisible, except for their eyes). This was also the only game that the company "Century 11" released.