According to ESRB, this game contains: Animated Violence
For those who like their boxing experiences way over-the-top, go with Ready 2 Rumble (preferably the Dreamcast version) and stay away from the N64 version of Knockout Kings 2000. Those looking for a more authentic interpretation of the sport, Knockout Kings 2000, despite its flaws, is attractive for its many impressive features. Its impressive lineup of boxers (which includes the WB's Marlon Wayans and NBA's Tim Duncan!?!) is simply unsurpassed and there's a level of dignity and respect for the sport. But be weary of the complex controls that will reward those who bone-up, but frustrate those looking for a quick fix.