Populous was a flagship game of the 16-bit era, creating a new genre from scratch and showing what computers such as the Amiga A500 and Atari ST were capable of. It was popular enough for 8-bit conversions to be attempted, and one of these abandoned efforts has surfaced decades later: a port for the Nintendo Entertainment System. It's amazingly accurate to the original, but with a tiny play area, presumably for performance reasons.
The game was fully completed by the Enigma Variations team for Electronic Arts/Bullfrog, but Mark Greenshields tells us that the client just decided not to proceed with publishing the title. Darren Melbourne (who was producer for the game), informs us that Imagineer decided that the NES was probably past its prime and they wouldn't achieve the necessary sales. Darren was pretty upset because they had put a lot of time and effort into creating the game.
A port to the Sega Master System was published, however. It has similar playfield constraints, but runs faster and with more colors.
Other official 8-bit versions were for the Game Boy (where simplification would have been more acceptable) and the PC Engine, which had a 16-bit graphics chipset. A Commodore 64 tech demo (from 1991) is impressive, but wasn't developed further.
Be sure to see the other historical oddities at Games That Weren't.
Previously: Design your own planet, Populous-style