How to play: Move the tetrominoes left and right with the arrow keys or buttons. Try to move the tetrominoes to get them to line up in horizontal rows. Use the up arrow to rotate the tetrominoes to fit holes. Complete full horizontal lines to raise the level. The more lines completed at once, the more you'll be challenged. Completing the maximum number of lines at once, four, is known as a 'Tetris' and can only be pulled off with straight, long rectangle tetrominoes.