Stargate/Versions

Apple II
Developed by Atarisoft in 1983.

Atari 2600
Developed by Atari in 1984. Considered surprisingly accurate. Later re-released as Defender II.

Atari 5200 & 400/800/XL/XE
Developed by Atari in 1984. As was typical for these two systems, the 5200 version was visually identical to the Atari home computer versions. This version was ultimately never released. A prototype version of the ROM was leaked to the public.

Commodore 64
Developed by Atarisoft in 1985. This version appears to be an unaltered version of an unofficial conversion of Defender known as Guardian.

IBM PC
Developed by Atarisoft in 1983.

NES
Developed by HAL. Released in Japan as Stargate in September, 1987. Released in the U.S. as Defender II in July, 1988.