Despite what the title may indicate, Sumo Fighter is not a sports game but a side-scrolling platformer. The player takes the role of a sumo wrestler who has to cross five levels (each with three stages plus a boss) to rescue his kidnapped girlfriend. The protagonist has two means of attack: his fists and a stomp attack which, in addition to the damage, can stun enemies. Experience points are awarded for killing enemies, solving hidden mini games and collecting power-ups like health refreshments or temporary invincibility. Eventually this leads to a level up and the player can choose to upgrade one of the two attacks or increase his maximum health. The mini games are sumo wrestling, arm wrestling and thumb wrestling. All are reaction tests in which a button has to be pressed to stop a cursor moving left and right at the correct spot.