Sumo Fighter is not a traditional sports game, but rather a side-scrolling platformer where you play as a sumo wrestler on a mission to rescue his kidnapped girlfriend. The journey takes you across five levels, each with three stages plus a boss, that you must overcome to reach the end.
The gameplay revolves around using two main attacks: your fists and a stomp attack. Your fists deal damage to enemies, while the stomp attack not only causes harm but also has a chance to stun them. As you progress through the game, you'll earn experience points by defeating enemies, solving hidden mini-games, and collecting power-ups like health refreshments or temporary invincibility. These points can be used to level up and upgrade your attacks or increase your maximum health.
The mini-games in Sumo Fighter are a series of reaction tests that require you to press a button at the correct spot to stop a cursor moving left and right. The three types of mini-games are sumo wrestling, arm wrestling, and thumb wrestling, each testing your reaction time and accuracy.