The game itself was an adaptation of the popular shooting gallery games that were a mainstay of carnivals. In this electronic 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 a hail of 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.
Video games had existed prior to Space Invaders, and the game Pong by Atari was already a few years old when this game was released. But Space Invaders captured the attention and imagination of the public in a manner paralleled by few games before or since. Its science fiction-based action and futuristic setting appealed to a public in the midst of Star Wars mania. The game's design included a touch of horror, as it gave players the illusion that they were in a desperate battle to save the world from alien invaders... a battle that they would eventually lose, as endless waves of electronic aliens would sweep down until they were overwhelmed. The simple background soundtrack to the game, which gave the impression of a beating heart, increased the tension and kept players coming back for more.
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. After a wave was completely eliminated, the next wave would begin (slightly lower on the screen) with the original, slow, speed. As it turned out this was not so much of a 'feature' as it was a 'bug'. Due to the way the game updated the screen, when an alien was destroyed the game and screen had one less object to draw and thus could draw the game screen slightly quicker. Since speed governing techniques were yet to be implemented into games, the updating of the screen governed the speed of the game. As more and more aliens were destroyed the game ran faster and faster, giving the false impression that the game was designed to become harder and faster. However, regardless of this, this 'bug' became a popular feature of the game.
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 projected (automatically) to a plastic panel which the player saw. Behind the reflective panel was a lunar landscape which gave the game an impressive background setting. Since the actual video game console itself had a monochrome video image, Taito added color by coating the reflective screen with colored bands.
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 quarters into the game at a frenzied pace. Video game mania among the youths in the United States was so pervasive that for a time, some children and teenagers were panhandling and begging strangers for quarters so that they could continue playing the game.
This phenomenon led to the first outcries against video games by groups of concerned adults, who felt that the content of video games was a corrupting influence on children. In the case of Space Invaders, the issue was not usually the highly abstract and stylized violence, but with the fact that the game could not be "won" in any familiar sense. As framed by the critics, the player is powerless to do more than to delay an inevitable defeat. They suggested that the game taught an unwholesome life lesson, inculcated defeatism, and possibly was intended to put the United States at a disadvantage in its economic rivalry with Japan by undermining the competitive spirit of American youth.
The home version of Space Invaders for the Atari 2600 was a huge success. Not only did it capture the look and feel of the original arcade version, but it also offered 110 different versions of the game. Variations included invisible invaders, invisible missiles and other subtle alterations. It was the first video arcade adaptation for the Atari 2600 system. 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 (some of which were less than successful).
Space Invaders spawned an enormous number of imitators, as other video game manufacturers sought to cash in on its successful formula. Dozens of similarly-themed video games were released to arcades in a short period of time afterwards, though nearly all of these games were variations of the same theme: attacking aliens from outer space.
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.