Space Invaders

Space Invaders is the game that turned arcades from a novelty into an industry. Tomohiro Nishikado built it around hardware that could barely keep up with the idea, and that limitation accidentally produced the most important design decision in the game.

Fifty-five aliens sit in five rows and march sideways, dropping one step closer every time the formation touches an edge. As you shoot them, there are fewer sprites for the board to draw, so the remaining ones move faster and faster - the game speeds up because the hardware is doing less work, not because anyone planned a difficulty curve. Kill the last alien on screen and the whole board resets one row lower. A mystery UFO crosses the top for bonus points, and the value of a shot depends on how far away you are. It was the first game to track a high score, the first to sell in the hundreds of thousands of arcade units, and in Japan it caused a documented shortage of 100-yen coins. The version captured on this page is Taito's SV board revision.

• ▸The aliens genuinely accelerate as their numbers drop
• ▸A mystery UFO crosses the top for variable bonus points
• ▸Each cleared board restarts one row closer to the player
• ▸The first game to record and display a high score