There were a few sequels to the game, including Galaga, Gaplus, and the laserdisc-based Galaxian3. In North America the machine was distributed, like many of the early Namco games, by Bally/Midway. Using the space invaders formula and speeding play up by having the bug-like enemies throw themselves at the player, Galaxian spawned a ton of rip-offs, clones, and homages, most of the earlier ones using the same hardware.
Before Galaxian, color overlays were used on arcade screens. Notable for being the first full color raster game ever. Namco's third in-house arcade game, released in 1979.
