Puyo Puyo Sun is the third game of the Puyo Puyo series. Unlike the original (arcade) Puyo Puyo and Puyo Puyo Tsu, which were developed for Sega's Genesis-based System C2 arcade hardware, Sun uses the Saturn-based ST-V architecture. Sun adds a new mechanic, Sun Puyo, to Puyo Puyo Tsu's ruleset. It also allows players to select a character before a multiplayer battle.
The emphasis on the sun is a pun based on the Japanese word for "three," san.
Puyo Puyo Sun's core rules are identical to those of Puyo Puyo Tsu. Players are given a 12x6 field and must match 4 Puyo of the same color together to eliminate them. "Popped" Puyo send gray Nuisance Puyo to the opponent; Nuisance Puyo can only be erased by popping a set of color Puyo next to them. The opponent has a chance to eliminate Nuisance that is waiting above their field by creating a chain of their own; this is called "offsetting." The first player that cannot bring new Puyo into their field (this is caused by filling the third column from the left) loses.
New to this game is Sun Puyo. A sun is located in the middle of the field; whenever a player offsets Nuisance Puyo, the sun turns red and glows. The sun will then drop Sun Puyo into their field; the player is warned of incoming Sun Puyo by beams of light that shine in the targeted columns. Sun Puyo offer bonuses to a player's score and, by extension, increases the number of Nuisance that the player will send to their opponent. Getting an All-Clear (clearing the entire field) also offers Sun Puyo; this replaces the Nuisance bonus that was given in Puyo Puyo Tsu.
Like the original Puyo Puyo, Sun's single-player mode is split into Easy, Normal, and Hard; each difficulty features a different player character.
The Easy route stars Draco Centauros, who seeks to enjoy the perpetual summer created by Satan.
Normal and Hard
The Normal and Hard routes star Arle Nadja and Schezo Wegey, respectively; both want to fix the weather. Arle battles every opponent, while Schezo starts at Komodo Dragon. The Hard route, like the single player mode of the previous two entries in the series, increases the Puyo drop speed as the player advances.