Press the Green Flag to start a fresh game (reset scores) and space bar to launch the first ball (will randomly go towards one or the other player) Green Paddle uses up and down arrows to move. Red Paddle uses W and S to move up and down. Ball accelerates each time a paddle is touched. If the ball touches a goal line, the last player to hit it gains a point. Space bar launches a new ball at the player who lost the last point.
Obviously, with much love to the original Atari pong team (and the Magnavox Odyssey tennis game they ripped off).
