The gameplay is basically the same as in Pong, except you have a protective bar in front of your character. You have to try to beat the opponent with the ball, but the first time it hits, it will do it against this protection. After that first hit, the protection disappears and you'll be able to strike a point.
The matches can be 1v1 or in pairs, in a specific number of sets. Normally, and unless players are particularly good, the matches last about five minutes.
JaPong is a fun sports game that offers a very similar experience to the traditional Pong, but featuring a twist that adds a lot of depth to it.