Galaxian was released by Namco in 1979 and represented a huge leap forward for arcade games. While Space Invaders had introduced the fixed shooter genre a year earlier, its aliens marched in rigid rows and everything was rendered in monochrome (or through coloured screen overlays). Galaxian changed all of that. It was one of the first arcade games to use true RGB colour, giving each row of aliens a distinct hue. The scrolling starfield background created a genuine sense of depth and movement that no game had achieved before.
The real innovation, though, was in the enemy behaviour. Instead of simply advancing downward in formation, Galaxian's aliens would peel away from the group and swoop toward the player in curved diving attacks, firing as they came. The flagship aliens at the top of the formation could take escort ships with them on their dives, and destroying a flagship with its escorts earned massive bonus points. This made every moment unpredictable and elevated the game from a shooting gallery into something far more dynamic. Galaxian laid the groundwork for its even more famous sequel, Galaga, released in 1981.