Galaxian

Developed and published in 1979 by Namco and published in North America by Midway, Galaxian (ギャラクシアン) is one of the earliest, competitive and succesfull shooters ever. It was design to compete with Space Invaders, another classic, but presented some new features like some drama (the aliens sometimes make kamikaze attacks), level bosses, and it was the first game to have all of its graphics in RGB colour.