Kunio no Oden takes place during the Nekketsu High tournament, where Kunio and his friends are determined to show off their skills in an eating contest. The game's story revolves around the excitement and competition among the participants as they aim to prove themselves as the ultimate champions.
The gameplay of Kunio no Oden is centered around a block-lining puzzle mechanism, similar to that of classic games like Tetris and Puyo Puyo. Players must line-up blocks of the same type as they fall in a rectangular play area, clearing them before time runs out or the screen fills up. The game features a 1P tournament mode and a 2P competitive Vs mode, allowing players to chain blocks together and send them to their opponent as attacks in an attempt to cause them to lose.