How to play Tetris Unblocked The Tetris Unblocked Online HTML 5game features Tetris blocks, also known as "Tetris," that have holes in them. These blocks are line after line of colored cubes that fall down when touches but bounce back up if they break. In order to line up the right block in order to make a line of three, you must guide the falling cube with the stick or your fingers in the shape of a flag. While breaking the bricks, they might shift position, and a new set of bricks could form. Once the bricks are gone, the game is over, and another try is started.