Back in 1992, Game Freak – now most famous for developing the insanely popular Pokémon series of video games – produced an adaptation of Tatsuya Egawa's million-selling manga Magical Taruruto for the Sega Mega Drive in Japan.
Released exclusively in Japan in April of 1992, Magical Taruruto-kun was directed by Ken Sugimori, produced by Satoshi Tajiri and featured music by Junichi Masuda. All three have become a massive part of Pokémon's success on Nintendo platforms.
Magical Taruruto appeared in Weekly Shōnen Jump from November 1988 to September 1992, and would also spawn an 87-episode anime TV series by Toei Animation, as well as three feature films.
It's listed as being in alpha, so expect some rough edges. You can download it here.
You can view the (untranslated) version of the game below.