The various modes available for play are the star of Puyo Puyo Tetris. They may implement the rules of Puyo Puyo, Tetris, or a new set of rules to incorporate both contrasting play styles into one hectic match.
The simplest mode, where the player may choose whether they want to play Puyo Puyo or Tetris. The opponent may either have a matching play style or a different one, though the rules are straight-forward to players familiar with the multiplayer modes of the original games; Puyo Puyo rules are based on Puyo Puyo Tsu while Tetris rules are based on classic multiplayer rules. Garbage blocks and clear Nuisance Puyo are sent to the other players as a chance to slow them down; this is done by line clears in Tetris and Chains in Puyo. Puyo players cannot use hard drop by default, but this setting may be changed in local battle and Club mode online. When up against a player using a different game mode, the strength of the attacks are converted to match the rules of the other mode, and the shape of the obstructing garbage/nuisance is converted to match it as well. Additionally, when playing Tetris with at least one Puyo player, the Tetris fields annex an "Attack Gauge" which stores attacks when performing a combo (REN in-game), and sends attacks altogether.
The aforementioned rule where Puyo and Tetrimino appear in one playfield. It is 8 blocks wide and 16 blocks tall, which is the average of the Puyo field (6x12) and Tetris field (10x20). When any block stacks on the red X's shown at the top of the 3rd-6th rows, the game is over. The size of a Puyo is the same as the size of a block of a Tetrimino, and while both can be cleared with their respective algorithms, the HOLD function can be used for Puyo as well. Puyo can be hard-dropped by default. This mode is made more complex by elements such as:
- I1, I2, and Special Puyo groups. This rule contains I1, the piece with one single block; I2, the piece with two blocks in a line; and a Special Puyo group that toggles between Puyo and Mino in a constant interval. The shape of the Special Puyo group is character-specific (e.g. Ringo and Tee's are T-mino shaped).
- The pattern of the pieces. In this rule, 3 or 4 Puyo can appear in a piece, as with Puyo Pop Fever rules and later, and each character has a different spawn pattern specific to this game mode. The common loop is: 6 character-specific Puyo groups, 2 Tetriminos, 2 Special Puyo groups, 6 Puyo groups (same shapes as the first 6), 2 Tetriminos, I2, 6 Puyo groups, 2 Tetriminos, I1. The minos in a loop are generated randomly with a bag randomizer, except for one, which is the character-specific Special Puyo group.
- Squashing. When soft-dropping a mino on Puyo, it sinks gradually to the bottom squashing the Puyo at the pace of 2 lines per second. When hard-dropping a mino on Puyo, it sinks instantly to the bottom. The squashed Puyo respawn from the top, except the Nuisance Puyo that disappear completely.
The rules are the same as VS, with the exception that both Puyo Puyo and Tetris must be played. The modes switch every 25 seconds for both players, and they must continue where they left off before being switched back to the other mode. This cycle is continued until the typical clear requirement is met: fill up either one of the opponent's fields while it is in play. If a Puyo or mino is falling as the switch occurs and it is not hard-dropped by the player, it will continue to drop on its own without any control. Meanwhile, if a chain is created in either Tetris or Puyo Puyo and it is switched before the effects can take place on the opponent's field, the attack will occur on the field that is currently in play, converting it as is done for differing modes in VS.
In Party Mode, players are given items that can have good (buff) and bad (debuff) effects. These effects can be for the player (self) or to others (opponent). Within 2 minutes, the player who earned the highest points will be the winner. Topping out or reaching the 'X' will not make the player lose, but other players will receive 1500 points. An item block is equal to the size of a single Puyo and the 'O' Tetrimino. Various items have the following abilities:
- Extra points when clearing lines/puyos (self)
- Steals points from other players (self, buff/debuff, opponent)
- Blocks garbage (self)
- Turns Tetriminoes into Pentominoes (to Tetris only, opponent)
- Covers all Puyo in ice (to Puyo only, opponent)
- Turns next pieces into a gold monomino (to Tetris only, self)
- Prevent pieces from rotating (opponent)
- Makes pieces fall down faster (opponent)
Both players are sent immediately to fever mode (Puyo) and Lucky Attack (Tetris). After one minute, all the garbage created by the players will be sucked into a black hole and "explode", thus the name Big Bang. Players who created less garbage than the others will take damage. If the a player's HP bar becomes empty, he or she will be eliminated. Last player standing will win. In the Puyo Puyo mode, players need to find the trigger puyo to start the chain. The chains of puyo become larger every time the player clears the previous one (denoted by 'CLEAR!'), and smaller if the chain did not reach the required number (denoted by 'MISS'). In the Tetris mode, Lucky Attack gives the player a pre-made stack where they must clear lines using the given tetriminoes. The given tetriminoes depend on the pre-made stack (a stack for T-spins gives the player T-tetriminoes). Each stack usually takes 5 to 7 line clears, and other stacks may allow all clears. If the player drops a tetrimino without clearing a line, the player "misses" and is given a new stack.
A simple single-player-only mode that consists of Puyo and Tetris challenges, including:
- Endless Puyo Puyo: Go for a high score in a never-ending game of Puyo Puyo.
- Endless Fever: Clear the given number of chains before time runs out.
- Endless Mini Puyo: A game featuring tiny versions of the Puyo on a normal-sized field.
- Marathon: Go for high scores before clearing 150 lines. After ever 10 lines, the game speeds up.
- 40-line: Get a best time when clearing 40 lines.
- Ultra: Get a high score within three minutes.