an arcade game for consoles and became the first "killer app" for video game consoles after quadrupling the system's sales. It sold over one million units in its first year on sale as a home console game, then over copies by the end of 1981, and over by 1982; it was the best-selling Atari 2600 game up until the Atari version of Pac-Man (1982). Space Invaders for the Atari 2600 had sold cartridges by 1983, and a further between 1986 and 1990, for a total of over cartridges sold by 1990. Other official conversions were released for the Atari 8-bit computer line and Atari 5200 console, while Taito later released it for the Nintendo Famicom in 1985, but only in Japan. By 1982, versions of Space Invaders were available for handheld electronic game devices, tabletop dedicated consoles, home computers, watches and pocket calculators. The Atari VCS conversion was programmed by Richard Maurer, while the Atari 5200 conversion was programmed by Eric Manghise and animated by Marilyn Churchill. More than a hundred Space Invaders video game clones were released for various platforms, such as the popular computer games Super Invader (1979) and TI Invaders (1981); the latter was the top-selling game for the TI-99/4A through at least 1982. Legacy As one of the earliest shooting games, Space Invaders set precedents and helped pave the way for future titles and for the shooting genre. Space Invaders popularized a more interactive style of gameplay, with the enemies responding to the player-controlled cannon's movement, and was the first video game to popularize the concept of achieving a high score, being the first to save the player's score. While earlier shooting games allowed the player to shoot at targets, Space Invaders was the first in which multiple enemies could fire back at the player, and in contrast to earlier arcade games which often had a timer, Space Invaders introduced the "concept of going round after round." It was also the first game where players were given multiple lives, had to repel hordes of enemies, could take cover from enemy fire, and use destructible barriers, in addition to being the first game to use a continuous background soundtrack, with four simple diatonic descending bass notes repeating in a loop, which was dynamic and changed pace during stages, like a heartbeat sound that increases pace as enemies approached. An urban legend states that Space Invaders' popularity led