Galaga

Galaga is a Japanese arcade game developed and published by Namco Japan and by Midway in North America in 1981. It is the sequel to 1979's Galaxian. The gameplay of Galaga puts the player in control of a spacecraft which is situated at the bottom of the screen, with enemy aliens arriving in formation at the beginning of a stage, either trying to destroy, collide with, or capture the spaceship, with the player progressing every time alien forces are vanquished.

(source-Wikipedia)