Back to the Future Part III (or Back to the Future III) is the title of a video game released for the Sega Genesis and is based on the film of the same name. The game is different from LJN's Back to the Future Part II & III video game released for the NES. The game was released in 1991 for the Sega Mega Drive/Genesis, Amiga, Amstrad CPC, Atari ST, Commodore 64, DOS, Sega Master System, and the ZX Spectrum. Each version of the game is more or less identical and are loosely based on the popular film of the same name. The game was developed by Probe Software and published by Image Works and Arena Entertainment (for Sega).
Source: Wikipedia, "Back to the Future Part III (video game)", available under the CC-BY-SA License.