Space Invaders

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Space Invaders
Space Invaders screenshot
Developer(s) Taito Corporation
Publisher(s) Midway
Designer(s) Toshihiro Nishikado - Game Designer
David Yuh - Programmer
Release date(s) 1978
Genre(s) Fixed Shooter
Mode(s) Single player
Platform(s) Arcade
Input Two motion buttons, one fire button, and two start buttons
Arcade cabinet Upright
Arcade CPU(s) 1x Intel 8080 @ 2.000 MHz
Arcade sound system(s) Texas Instruments SN76477
Arcade display Monochrome raster, vertical orientation

Space Invaders is an arcade video game designed by Toshihiro Nishikado in 1978. It was originally manufactured by Taito and licensed for production in the U.S. by the Midway division of Bally. Released (at first in its native Japan) in 1978, it ranks as one of the most influential video games ever created. Though simplistic by today's standards, it was one of the forerunners of modern video gaming.


Inspired by Taito's earlier electromechanical machine Space Monsters and and Toshiro's interpretation of alien descriptions in War of the Worlds, the game itself resembled an adaptation of the two. In this video game version of the game, the player controlled the motions of a movable laser cannon that moved back and forth across the bottom of the video screen. Rows and rows of video aliens marched back and forth across the screen, slowly advancing down from the top to the bottom of the screen. If any of the aliens successfully landed on the bottom of the screen the game would end. The player's laser cannon had an unlimited supply of ammunition to shoot at the aliens and destroy them before they hit the bottom of the screen.

Meanwhile, the aliens would shoot back at the player, raining deadly rays and bombs that the player would have to dodge lest his cannon be destroyed. The player's cannon could be destroyed three times (the player had three lives), and the game would end after the player's last life was lost. Occasionally a bonus spaceship would fly across the top of the screen which the player could shoot for extra points.

As the player destroyed an increasing number of aliens, the aliens began marching faster and faster, with the lone remaining alien zooming rapidly across the screen. Shooting the last alien in the formation rewarded the player with a new screen of aliens, which began their march one row lower than the previous round.


Mirrored holographic display and cardboard background of a Midway Space Invaders Deluxe arcade cabinet. Note the monitor on the bottom.
Mirrored holographic display and cardboard background of a Midway Space Invaders Deluxe arcade cabinet. Note the monitor on the bottom.

One key feature of Space Invaders was the fact that as more and more of the aliens were shot, the remaining aliens would move faster and faster. The change in speed was minor at the beginning of a wave, but dramatic near the end. This action was originally an unintentional result of the way the game was written - as the program had to move fewer and fewer aliens, it could update the display faster - but the development team decided to retain this feature rather than implementing busy waiting when there were few invaders on the screen.

Space Invaders used an Intel 8080 as its processor, running at 2 MHz. Graphics were implemented through a 1 bpp frame buffer mapped from the main CPU address space. All sound effects were implemented individually with discrete electronics.

The Japanese version of the Space Invaders arcade cabinet.  (Note Joystick)
The Japanese version of the Space Invaders arcade cabinet. (Note Joystick)

In the upright version the actual output of the game was displayed mirror-image on a black and white monitor which sat recessed in the game's cabinet. The image was reflected on a plastic panel which the player saw. Behind the reflective panel was a lunar landscape which gave the game an impressive background setting. It is interesting to note that there were two major uprights. There was the original Taito upright which utilized joystick control, but most people in America are familiar with the Midway licensed version which used directional buttons and arguably had inferior artwork on its bezel, side art, and moon backgrounds.

Since the actual video game console itself had a monochrome video image, Taito added colour by coating the reflective screen with colored bands. It should be noted however, that the very first version of the game in Japan ("T.T.", or "Table Top" Space Invaders) was a cocktail table with purely black and white graphics (i.e., no colour overlay). There was also a version of the game in which the graphics were converted to actual RGB colour.

Space Invaders had no hardware for the generation of random numbers, so the seemingly random point values awarded by the UFO actually utilized a hash function based on the number of shots that the player had fired in the current invasion wave. It did not take long for experimenters to determine that the maximum 300-point value could be achieved every time if the player shot the wave's first UFO on the 23rd shot, and subsequent UFOs at 15-shot intervals thereafter. Later revisions of the game removed this "bug".

Another important tactical element of the arcade game is that it is impossible for the players' spaceship to be harmed by an invader firing a missile from the lowest line on the screen before the invader lands.

Graphics design

In October 2005, Nishikado commented in an interview with English based video games magazine Edge that the look of the aliens had been based on the description of the alien invaders in H. G. Wells' classic science fiction story, The War of the Worlds: "In the story, the alien looked like an octopus. I drew a bitmap image based on the idea. Then I created several other aliens that look like sea creatures such as squid or crab." Nishikado also noted that his original intention in designing a shooting game had been to make the enemies airplanes, but that this had been too technically difficult to render. He was opposed to depicting the enemies as human beings (which would have been technically easier) as he believed the idea of depicting the shooting of humans to be "morally wrong".


Popular response

The enormous blockbuster success of Space Invaders made the entertainment industry sit up and take notice. Within the first year of its release, the game had generated revenue ranging in the hundreds of millions of dollars—with the majority coming from teenagers and school children, who pumped millions of coins into the game at a frenzied pace. In Japan, Space Invaders caused a coin shortage until the Yen supply was quadrupled .

Space Invaders became very popular in part due to its new style of game play. Up until its release, video games were timed to a clock, and once a player's time was up (plus possible bonus time), the game ended. With Space Invaders, the game ended only when the player had exhausted the three allotted "lives" or when the invaders landed on the bottom of the screen: a person could therefore play for as long as their skill level allowed.

Highest Score

According to the book Stratford Video Gaming Records, 1980 Premiere Edition (pg. 79), at the Canadian National Exhibition, held between August 29 and September 2, the following are the records set in continuous play of the game:

1st Place (NEW RECORD)

Score: 1,114,020
Play Time: 38 Hours, 30 Minutes
Particulars: TOTAL OF 4 BASES, 111 SCORE ROLLS (0000 - 9990)
Pauses: (7) 15min., excluded from play time

2nd Place (NEW RECORD)

Score: 98,390
Play Time: 3 Hours, 12 Minutes
Particulars: TOTAL OF 4 BASES, 9 SCORE ROLLS (0000 - 9990)
Pauses: None

3rd Place (1980 RECORD)

Score: 23,710
Play Time: 59 Minutes
Particulars: TOTAL OF 4 BASES, 2 SCORE ROLLS (0000 - 9990)
Pauses: None

Later releases

The home version of Space Invaders for the Atari 2600 was a huge success. It offered 112 different versions of the game. Variations included invisible invaders, invisible missiles and other subtle alterations. It was not the first video arcade adaptation for the Atari 2600 system (most of the early games for the 2600 were adaptations of early Atari video arcade games such as Breakout, PONG, Night Driver, etc.), but it was the first officially licensed arcade game for home conversion from one company to another (in this case, Taito to Atari.) Other home console companies would make their own conversions of Space Invaders. Examples included Space Armada for the Intellivision, Alien Invaders — Plus! for the Odyssey 2 and TI Invaders for the TI-99/4A. But only Atari owned the rights to the use of the title Space Invaders. The console had been released in 1977, but sales of the 2600 skyrocketed during the 1980 holiday shopping season, as millions of families bought the Atari system just so that they could play Space Invaders. This marked the beginning of home video adaptations of popular arcade games.

Space Invaders spawned a large number of imitators, as other video game manufacturers sought to cash in on its successful formula, and released many arcade games featuring variations of the same theme: attacking aliens from outer space. One such example was a game called Pepsi Invaders, made by Atari at the request of Coca-Cola for their Atlanta employees. Taito released several sequels to Space Invaders in the arcades over the years:

  • Space Invaders Part II (" Space Invaders Deluxe") (1979)
  • Return of the Invaders (1985)
  • Majestic Twelve: The Space Invaders Part IV (" Super Space Invaders '91")


  • Space Invaders DX (1994)
  • Akkan-vaders (" Space Invaders '95: The Attack Of The Lunar Loonies") (1995).

The release of Pac-Man in 1980 broke the mold of "alien invader" games, and it opened the way for more creativity and originality in the video gaming industry. But the legacy of Space Invaders lives on, and action-based science fiction games continue to pay homage to the original shoot-em-up video game.

Enemies based on Space Invaders also appeared in Bubble Bobble games. To top it off, Bubble Symphony featured both a giant Space Invader guarded by aliens who move just like in Space Invaders as a boss and cameo appearances by the player controlled spaceship as a companion for the main characters.

Super Space Invaders was a Space Invaders clone for a range of systems including the Amiga, Master System and Super Nintendo Entertainment System featuring greatly upgraded graphics and sound, along with additions to the game play such as power-ups and advanced forms of aliens. Despite this, it was given average reviews at best, and sold very poorly.

Space Raiders (Space Invaders: Invasion Day in Europe) was released in 2001 and is a 3D version of space invaders. Rather than a laser at the bottom shooting up, the player is a human shooting forward at aliens in the street.

Space Invaders, Space Invaders Part II, and Return of the Invaders were re-released in October 2005 as part of Taito Legends for the PlayStation 2, Xbox, and PC. The other three arcade Invader games, Space Invaders DX, Super Space Invaders '91 and Space Invaders '95: Attack of the Lunar Loonies are scheduled for re-release in the Fall of 2006 as part of Taito Legends 2 for the same platforms.

In April 2007, Space Invaders Trilogy which includes arcade versions of Space Invaders, Space Invaders Part II, and Return of the Invaders was released for Pocket PC and Smartphone.

Street art

An Invader mosaic seen in Avignon.
An Invader mosaic seen in Avignon.

Space Invaders has also inspired a form of street art to a French artist known only by the pseudonym " Invader". Using ceramic tiles, Invader cements together mosaic images inspired of traditional Space Invaders aliens, bonus spaceships, and variations on those themes, sometimes including characters from the Pac-Man series, Super Mario series, and other video games. Most of the mosaics tiles are small and others are as large as murals. The mosaics are cemented onto building walls, lamp post bases, and other structures. The form has spread throughout the world since the 1990s, among more than 30 cities over 5 continents, Invader is still in activity. Some of the thousands of individual Invaders have been documented with photographs on Invader's website.

Human Space Invaders

In 2006 at the Belluard Bollwerk International 06 festival in Fribourg, Switzerland, Guillaume Reymond of NOTsoNOISY created a 3 minute video recreation of Space Invaders using humans as pixels. This is part of a larger project called the "Gameover" project which also includes Human Pong.

Easter Egg

  • On the Atari 2600 version of this game a single player can obtain "double bullets" by turning the game on while holding down the game reset switch. After choosing single player, 2 bullets are fired for each press of the button. This dramatically changes the nature of the game and allows players to obtain a much higher score.
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