Greatest Heavyweights is a boxing simulation game released in 1994 for the Sega Genesis. As an extension of the 'Evander Holyfield's Real Deal Boxing' series, it features a roster of legendary fighters like Muhammad Ali, Joe Frazier, and Rocky Marciano. Players can compete in exhibition matches or undertake a career mode, fighting to rise through the ranks for a championship title. With a mix of fast-paced in-ring action and strategic career management, this sports title offers robust customization for creating and training your own boxer, honing a unique fighting style for the squared circle.