Galaxian | Code Like It's 198x

In Space Invaders the aliens march; in Galaxian they attack. The formation still hangs at the top of the screen, but every few seconds one alien, or a flagship with two escorts, peels away in a half-loop and swoops down at the player’s ship, dropping bombs as it comes. Namco released it in 1979, when arcades were full of games copying Taito’s hit, and it changed what a shooting game could be. Tomohiro Nishikado, who had designed Space Invaders, remembered the moment he saw it: “When I saw how smooth the movement was in Namco’s Galaxian, and how colourful it was, too, I remember thinking Space Invaders had lost.”

Fast facts

Developer: Namco, 1979: October in Namco’s own game history, September in some later accounts.
Designer: Kazunori Sawano, with Koichi Tashiro.
American licensee: Midway, which sold 45,000 machines.
Hardware: a Z80 processor, a character screen for the formation, sprites for the attackers, a hardware starfield, and colour from a small palette PROM.
Sequel: Galaga (1981).
Home versions: Atari for the 2600, 5200 and 400/800; Atarisoft for the Spectrum; a Coleco tabletop game.

What changed

By 1979, Wireframe observed, rival makers had filled arcades with games “almost all of them sticking rigidly to the Space Invaders template”, with names like Beam Invader, Space Attack and Cosmic Monsters. Galaxian kept the idea of a formation to shoot at and changed what the formation did. In Ryan Lambie’s account, Sawano looked at Space Invaders and asked “What if those aliens didn’t just move back and forth across the screen, but broke off in little formations and attacked the player?”

The result looked cleverer than it was. “In reality, the programming that drives the aliens’ AI is quite simple,” Wireframe explained: an alien always leaves the formation the same way, with a half-turn to the left or right, then descends in a side-to-side weave, and rejoins the formation if it reaches the bottom of the screen. With many aliens diving from different places, the game gives “the illusion of a swarming intelligence”.

Scoring rewarded nerve. Electronic Games explained in 1982 that “the flagships can attack with Galaxian escorts, and point values are affected by the number of escorts destroyed ahead of the flagship”. An alien shot in the formation was worth far less than one shot in the middle of a dive. The name, Retro Gamer has pointed out, belongs to the player, not the enemy: the attract screen introduces “the Galaxians”, defenders of the Earth.

Colour from the hardware

Space Invaders was drawn in one colour, and its cabinets got their colour from strips of cellophane on the screen. Galaxian produced its colours electronically. MAME’s emulation, built from the board’s schematics, shows how. A small PROM of 32 bytes holds the palette; each byte gives three bits of red, three of green and two of blue, so every colour came from a range of 256, and the 32 entries form eight sets of four colours. The formation is a screen of 8×8 characters, and each horizontal strip of it has its own sideways scroll position and one of the eight colour sets, which is why each row of aliens has its own colour and can slide sideways as a unit.

The attackers are different. When an alien dives, the game deletes it from the character screen and draws it as a sprite in exactly the same place, a trick the programmer Lee Taylor described to Edge when explaining why Galaxian was hard to emulate. The board has eight sprite slots, but it prepares sprites during the brief gap between scanlines, and MAME’s notes on the timing show that only seven and a half fit into that gap. Bullets are not sprites at all: the hardware can draw one white shell and one yellow missile on each line, counted out by dedicated counters as the beam passes. The twinkling stars come from a 17-bit random-number circuit that also supplies the noise for the explosions.

Namco’s colour was striking, but later claims that Galaxian was the first colour arcade game go too far. Amiga Format called it “the first ever colour arcade game” in 1999. MAME dates other colour machines to the same year, among them Taito’s own colour “CV” version of Space Invaders and Denki Onkyo’s Heiankyo Alien, and public sources do not settle which came first.

The design outlived the game. MAME’s driver lists dozens of games built on Galaxian’s hardware or copies of it, among them Nichibutsu’s Moon Cresta, Namco’s King & Balloon and Konami’s Scramble and Frogger, as well as a long line of bootlegs and hacks. Pac-Man was not one of them: it had a board of its own.

Midway and America

Midway, which had built Space Invaders under licence from Taito, took Galaxian too. MAME holds its version as “Namco (Midway license)”, differing from Namco’s only in where the “BONUS SHIP” message appears. Video Games reported in December 1982 that Midway had sold 45,000 Galaxian machines, after 72,000 Space Invaders. The relationship continued with Pac-Man and Galaga. Galaxian was a trademark of Bally Midway, licensed by Namco-America, in Atari’s notices of 1984.

The name also spread through a mistake. Midway’s Gorf (1981) included a cut-down version of the game as one of its five missions and called it “Galaxians”, and Retro Gamer traces the common plural to it. British programmers used it too: Superior Software and the young Matthew Smith both started out with Galaxians clones.

Galaga

Galaga followed in 1981. Its designer, Shigeru Yokoyama, was asked to make another shooter “in the Galaxian vein”, Wireframe recounts, and added a tractor beam with which a Boss Galaga could capture the player’s ship. Winning it back gave the player two ships side by side and double the firepower. Retro Gamer calls Galaga “a fuel-injected remake” that added “Challenging Stages”, bonus rounds of swooping aliens that neither shoot nor ram. It became the better-remembered game of the two.

At home

The home versions came from Atari, under licence. ANALOG Computing reported that Atari had “rushed out” Defender and Galaxian for its 400 and 800 computers for Christmas 1982, and was unimpressed: Galaxian “does not even come close to the Midway classic in either playability or screen display”. The Atari 5200 cartridge sold for $39.95 through Atari’s own club in January 1983, advertised on “the swooping attack patterns of Galaxian”. Britain’s TV Gamer reviewed the 2600 cartridge at £29.99 in September 1983 and found its graphics “much better” than Space Invaders’s, calling it “a souped up, faster-paced version of Space Invaders”.

Atarisoft, Atari’s label for other companies’ machines, advertised Galaxian on cassette for the Spectrum in 1984, with a VIC-20 cartridge to follow. Coleco made a tabletop version with a vacuum fluorescent display, which Electronic Games called “the most elegant tabletop game ever released”, adding a head-to-head mode for two players. Namco kept the game in print on later consoles, and Retro Gamer counted at least 12 re-releases in the ten years to 2006.

Sources

Edge issue 8, May 1994, pp. 54–61: Namco feature and game history (Galaxian, October 1979).
Wireframe issue 2, November 2018, pp. 32–33, Ryan Lambie, “Source Code: Galaxian’s dive-bombing aliens”: the Space Invaders clones, Sawano and Tashiro, the dive pattern and the “illusion of a swarming intelligence”.
Wireframe issue 39, May 2020, pp. 112–113, “Killer Feature: Galaga”: Sawano’s question, Shigeru Yokoyama and the tractor beam.
Retro Gamer issue 32, 2006, pp. 69–75: the Galaxian series (the player as “the Galaxian”, Gorf and “Galaxians”, Galaga’s Challenging Stages, the re-releases).
Retro Gamer Collection, vol. 4 (2010), pp. 247–251, Jonti Davies, “The Making of: Space Invaders”: Nishikado on Galaxian.
Edge issue 46, June 1997, “The forgotten history of the videogames industry”, part 2: Lee Taylor on Galaxian’s characters and sprites.
MAME source code, src/mame/galaxian/galaxian.cpp and galaxian_v.cpp (Aaron Giles and others): the CPU, sound and star circuits, the colour PROM, per-strip scroll and colour, the sprite and bullet timing, the Midway set and the games on the hardware; src/mame/midw8080/8080bw.cpp and src/mame/sega/vicdual.cpp: Space Invaders (CV version) and Heiankyo Alien, 1979; src/mame/pacman/pacman.cpp: Pac-Man’s own hardware. https://github.com/mamedev/mame
Amiga Format issue 127, September 1999, p. 83: “the first ever colour arcade game”.
Video Games (Pumpkin Press), vol. 1 no. 3, December 1982, pp. 52–55: Midway’s sales of Space Invaders and Galaxian.
Atari Age vol. 1 no. 5, January 1983, p. 19: Atari 5200 Galaxian, $39.95. Vol. 2 no. 5, March 1984, p. 4: trademark notice.
ANALOG Computing issue 10, March 1983, p. 16: Atari’s 400/800 Galaxian.
TV Gamer, September 1983, p. 27: Atari 2600 Galaxian (CX2684, £29.99).
Sinclair Programs, February 1984, p. 4: Atarisoft advertisement.
Electronic Games vol. 1 no. 6, August 1982, pp. 86–88, Joyce Worley: Coleco’s tabletop Galaxian and the arcade scoring.
Wikipedia, “Galaxian” (web, secondary): release dates and credits. https://en.wikipedia.org/wiki/Galaxian