Stack the falling blocks and clear full rows before the pile reaches the top.
Arrow keys or A / D move, Up or W rotates, Down or S drops faster, Space drops instantly, P pauses. On a phone, use the buttons under the board.
Blocks of four squares fall one after another. Move and turn each one so that it fills a complete horizontal row. A full row disappears and scores points; clearing several rows at once scores much more. Every ten lines the blocks fall faster. The game ends when the stack reaches the top.