I don't know what country you are from, but a role-playing game series with the same title was released in Japan for the Game Boy by Banpresto starting in 1990. I stumbled upon this completely unrelated game while searching for the JRPG series Oni. Perhaps the title should be changed? "Oni" means "demon" or "ogre" in Japanese, yet the content of this game appears to have nothing to do with such creatures.