For free online Tetris, use the up arrow key on your keyboard to change the falling shape to different positions. Use the left and right arrows to move the shapes horizontally. Use the down arrow to send the piece down in the position it is in. This free Tetris online game is fun and addictive to say the least and it’s actually good for your brain! In a 2009 study, people who played Tetris for 30 minutes a day for three months developed thicker cortexes in their brain than the control group who did not play. List your high score, number of lines, level, etc. in the comment section below.