Use W and S to move the left paddle. Use I and K to move the right paddle. If the ball touches a paddle, the floor, or the ceiling, it bounces off. If the ball bounces off a paddle, it will bounce more diagonally if it bounces from the edges and more horizontally if it bounces from the center. If the ball touches one of the walls behind each paddle, then the player who doe not control that paddle earns a point, and the ball's position is reset and re-oriented towards the losing player.
Big thanks to Matt Batwings for the explanation on how the original Pong by Atari works. I would have never been able to make this project without you.