In Tetris Attack, the player is presented with a playfield consisting of a virtual grid of squares, each of which can be occupied by a colored block. Blocks are stacked on top of one another and rise steadily toward the top of the playfield, with new blocks being added at the bottom. The player must arrange blocks in horizontal or vertical lines of three or more matching colors by swapping blocks horizontally two at a time. As matching lines are formed, the blocks are cleared from the screen and any blocks above them fall into the gaps. The game is over when the blocks touch the top of the playfield, or another game-ending condition is met (such as reaching a time limit or clearing blocks below a set line).