Move your mouse to move the paddler, or don't. The game can detect if you're AFK, and if you are, the computer will move the paddler to the best of its ability. A ball is bouncing across the screen. The more times it is hit, the faster it becomes.
FUN FACT / NOTICE: This game is called "Computer Rambling" because the AI that replaces the player when AFK. The AI always tries to get the ball stuck. A noise will be made when this happens, but it will be much shorter when the ball is normally hit. When the ball is stuck, the speed of it gradually increases with every frame (as demonstrated by the Speed/Steps variable). Leave it alone for a while and see how fast you can make it!