Knockout Kings 2003 is a sports game in which players engage in realistic boxing matches, utilizing various fighters and advanced control mechanics to simulate the sport. In this game, players can compete against AI or other players, with options to customize fighters, adjust round durations, and choose different fight modes, including career and exhibition. It stands out with its detailed fighter models, realistic injury and facial damage effects, and the inclusion of women's boxing, along with features like CPU vs CPU bouts and fantasy match-ups, offering a comprehensive boxing experience.