Galaxian expanded on the formula pioneered by Space Invaders. As in the earlier game, Galaxian features a horde of attacking aliens that exchanged shots with the player. In contrast to Space Invaders, Galaxian added an element of drama by having the aliens periodically make kamikaze-like dives at the player's ship, the Galaxip. This made it the first game to feature enemies with individual personalities. The game's plot consists of a title screen that displayed the message "WE ARE THE GALAXIANS / MISSION: DESTROY ALIENS".

Galaxian was very successful for Namco and introduced several "firsts". Although not the first color video game, Galaxian took RGB color graphics a step further with multi-colored animated sprites and explosions, different colored fonts for the score and high score, the scrolling starfield, and graphic icons that show the number of ships left and how many rounds the player had completed. It also features a crude theme song and more prominent background "music." These elements combine to create a look and feel that would set the standard for many other 1980s arcade games such as Pac-Man.

The game was developed by Namco in 1979, and released in Japan that year. It was designed to build and improve upon the formula of Taito's game Space Invaders, which had revolutionized the gaming industry upon its release a year earlier. Galaxian incorporated new technology into its dedicated arcade system board, the Namco Galaxian. Unlike Space Invaders, which was black and white and featured enemies that could only move vertically and horizontally as they descended, Galaxian had a color screen and enemies that descended in patterns and came from various directions. The result was more complex and difficult game play.

In 1980 Namco partnered with the American company Midway to release the game in North America. Midway had previously published Space Invaders in the market, but had to seek new foreign partners when Taito decided to market their games themselves.

Standard arcade games

• Galaga (1981)
• Gaplus (1984)
• Galaga '88 (1987)
• Galaga Arrangement (1995) - released as part of Namco Classic Collection Vol. 1

• Galaxian was one of the most widely pirated motherboards during the early 80s. Numerous hacks were made of the game and featured slightly redesigned aliens and special bonus stages. The scrolling starfield and the lose-a-life explosion was still familiar as the one from Galaxian.

Arcade laserdisc

• Galaxian 3 (1990) Galaxian 3 : Project Dragoon (Theatre 6) for 6 Players on 2 x 110 inch RGB Projectors - 18-foot-wide (5.5 m) screen
• Attack of the Zolgear (1994) (A ROM and laserdisc upgrade for Galaxian 3)

On release, Home Computing Weekly gave the Spectrum version of the game 3/5 stars describing it as a well-written version and praising the graphics as fast although flickery.Famicom Tsūshin scored the Game Boy version of the game a 24 out of 40.

Galaxian has spawned several follow-up games. The most popular of these was its immediate successor, Galaga, which largely eclipsed its predecessor in popularity, introducing aliens attacking in intricate formations, multiple guns, and bonus rounds. A third official sequel, Gaplus, was released in 1984. Like Galaga, this was a bottom shooter, with some limited up/down movement (like Centipede). However, by 1984 the novelty of the Space Invader formula had faded, and it was no longer successful.

Ports

The original arcade version of Galaxian has been ported to many different systems. These include:

Coleco also released stand-alone Mini-Arcade tabeletop versions of Galaxian, which, along with Pac-Man, Donkey Kong, and Frogger, sold three million units combined. A port for the Game Boy Color was planned, but never released.

Galaxian has also been released as part of the Namco Museum series of collections across several platforms:

• Dreamcast (Namco Museum)
• Game Boy Advance (Namco Museum Advance)
• Nintendo 64 (Namco Museum 64)
• Nintendo DS (Namco Museum DS)
• PlayStation (as part of Namco Museum Volume 3)
• PlayStation 2, Xbox, Nintendo GameCube and Microsoft Windows (Namco Museum: 50th Anniversary Arcade Collection)
• PlayStation Portable (Namco Museum Battle Collection)
• Wii (Namco Museum Remix)

Galaxian was also released on Microsoft Windows in 1995 as part of Microsoft Return of Arcade. The game was also released as part of the Pac-Man's Arcade Party 30th Anniversary arcade machine.

The game has also been seen in Jakks Pacific's "Plug It In & Play" TV game controllers.

Galaxian, along with Galaga, Galpus, and Galaga '88, was "redesigned and modernized" for an iPhone app compilation called the Galaga 30th Anniversary Collection, released in commemoration of the event by Namco Bandai. The collection app comes with Galaxian as a free game, with the remaining three games available in-app for $3 each or the complete set for $8. The app also features "Galaga points", collected as the games are played and used to unlock various consumable power-ups and special arcade cabinet designs, including the original art for each game.

Games featuring elements of Galaxian

• Entex Industries released a handheld electronic game called Galaxian 2 in 1981. The game is called Galaxian 2 because it has a two-player mode. It is not a sequel, as there is no Entex Galaxian.
• The video game Gorf, by Bally Midway, has a Galaxian stage.
• A version of the game can be unlocked in Midway's Mortal Kombat 3 on the Sega Genesis.
• The game can be seen on the home stretch of various Ridge Racer circuits. On the PlayStation version, while the player is waiting for Ridge Racer to load, they can play a quick game of Galaxian. Also, on Ridge Racer 64 and Ridge Racer DS, a car is available called the "Galaxian Paradise" (in Ridge Racer 64, the car is named "White Angel" like Ridge Racer and Ridge Racer Revolution).
• The boss of the Space Zone in the game Pac-Man World for PlayStation is inspired by the game Galaxian. However, the stage itself is similar to Galaga.
• Japanese RTS game New Space Order by Namco Bandai Games is set in the same U.G.S.F. universe as the setting of Galaxian.

Games featuring the Galaxian flagship

The Galaxian flagship (also called the Galboss) has made numerous cameo appearances in other Namco games (like the Special Flag from Rally-X) and would also go on to become a recurring item in other games).

• Pac-Man (1980): The flagship makes an appearance as a bonus fruit on rounds 9 and 10, and is worth 2000 points if Pac-Man eats it.
• Galaga (1981): The flagship makes an appearance as one of the "transform" ships. It splits into 2, then 3 clones of itself. If all 3 are killed, they are worth 3000 points.
• Dig Dug (1982): The flagship makes an appearance as a bonus vegetable on rounds 16 and 17, and is worth 7000 points if Dig Dug picks it up.
• Super Pac-Man (1982): All regular edible items on rounds 15, 31, 47, and 63 are flagships, and they are worth 150 points each. Starting from their second appearance, Round 31, they are 160 points instead.
• Pac-Man Plus (1982): The flagship's role is exactly the same as its role in Pac-Man.
• Pac & Pal (1983): The flagship makes an appearance as one of the "special items" that make Pac-Man turn blue when eaten, and allows him to stun the ghosts for a short while by shooting a Galaga style capture beam. It is worth 1000 points if Pac-Man eats it.
• Pac-Land (1984): The ghosts in airplanes sometimes drop flagships and they are worth "7650" points (765 being Namco's goroawase number in Japanese) if eaten.
• Super Xevious (1984): The flagship makes an appearance in a silver form and as an enemy, and sometimes several of them attack at once. They are worth 300 points each.
• Quester (1987): In Round 5, the bricks form a Galaxian Flagship.
• Pac-Mania (1987): The flagship makes a 3-D appearance as a special item and in 2 forms as well, the other one being the silver form from Super Xevious. The regular one and the silver one is 7650 points if eaten.
• Pistol Daimyo no Bouken (1990): The flagship makes an appearance as an enemy along with the other Galaxian characters, and they attempt to hit Pistol Daimyo with their fire.
• Tinkle Pit (1993): The flagship also makes an appearance with the other Galaxian characters, but this time they appear as bonus items. It is worth 800 points if collected.
• Tekken (1994 - Arcade, 1995 - PlayStation) and Tekken 2 (1995 - Arcade, 1996 - PlayStation): Winning at least seven rounds in Arcade Vs. mode will reveal the Galaxian flagship on the lower left (or right) hand corner of the screen. In order for this to work, "Number of Wins Shown By" must be set to "Fruit".
• Namco Classic Collection Vol. 1 (1995): The flagship makes an appearance in Galaga Arrangement as a Challenging Stage enemy in Space-Plant Zone (Stage 20) and Normally in Space-Flower Zone (Stage 26). If killed normally, they are worth 150 points. If killed in Challenging Stage, they are worth 300 points.
• Namco Classic Collection Vol. 2 (1996): The flagship appears in both Pac-Man Arrangement and Dig Dug Arrangement. In Pac-Man Arrangement, the Galaxian Flagship makes its appearance in World 4-1 and 4-2 and it is worth 5000 points if Pac-Man eats it, and in Dig Dug Arrangement, they appear in Stages 17 and 18 and it is worth 7000 points if Dig Dug picks it up.
• Pac-Man World (1999): The flagship appears again in a Pac-Man game. This time, the item must be collected in order to access the mazes.
• Pac-Man World 2 (2002): The flagship teleports Pac-Man to mazes. The point value will be the same as the points earned in the maze (if completed), plus 2,000.
• Pac-Man World 3 (2005): The flagship has the exact functionality as it does in Pac-Man World 2.
• Namco Museum Battle Collection (2005): The arrangement versions of Pac-Man and Dig Dug, later called Pac-Man Remix and Dig Dug Remix in the iOS version, feature the flagship. Pac-Man Remix features both the flagship, worth 3200, and the red drone, worth 2800, as fruit items, while on Dig Dug Remix, the flagship is a vegetable item and is worth 7000.
• Dig Dug: Digging Strike (2005): Just like the first Dig Dug, the flagship appears as a vegetable on stage 13, except it's worth 6000 points.
• Pac-Man Championship Edition (2007): The flagship reappears, but is this time joined by the Galaga Boss, Queen Gaplus, and two drones, one each from Galaga and Galaxian.
• Pac-Man Championship Edition DX (2010): The flagship and Galaga/Galaxian drones, Queen Gaplus and the Galaga Boss serve the same purpose as the original Championship Edition.
• Tekken Tag Tournament 2 (2012): The character customization allows you to add decals to the fighter's clothes. These decals include the flagship, along with other classic Namco sprites.

In the competitive arena

The Galaxian world record has been the focus of many competitive gamers since its release. The most famous Galaxian rivalry has been between British player Gary Whelan and American Perry Rodgers, who faced off at Apollo Amusements in Pompano Beach, Florida, USA, on April 6–9, 2006. Whelan held the world record with 1,114,550 points, until beaten by newcomer Aart van Vliet, of the Netherlands, who scored 1,653,270 points on May 27, 2009 at the Funspot Family Fun Center in Weirs Beach, New Hampshire, USA.