This head-to-head puzzle game tasks players with clearing their grid of falling pieces, known as puyos, by arranging four or more of the same colour into straight lines or other recognised patterns. Its competitive element comes from the fact that clearing puyos sends random filler pieces to the opponent’s grid. Larger clears generate more filler, increasing the pressure on the opposing player. A round is won by filling the opponent’s grid to the top. The game also includes a light narrative framework for solo or multiplayer play.

Unlike the first game’s linear Scenario mode, *Tsu* centres on a tower-based main mode in which Arle Nadja selects opponents through a roulette system. Each floor has an experience-point requirement that must be met to progress. If all opponents on a floor are defeated before reaching that target, a final extra opponent appears. If the required total is still not reached after that battle, Arle is expelled from the tower, and the game ends.