Opposites is a Tetris-style competitive puzzle game. Two players play simultaneously on the same field; one player adds white pieces from the left while the other adds black pieces from the right. Solid objects on one side become open space on the other. If a player completes a line of their color, that line vanishes and the field shifts toward the other player. When one player's open space reaches the other player's edge, they win the game. Opposites can be played either against the computer or with a second player.