Which version did you test? With a tree in the background? In the version without the tree, the computer serves and the physics is improved, although still not perfect, because it is very difficult to accurately read the speed of the mouse movement. In addition, the mouse is very sensitive, if I would translate all its speed into the movement of the ball - the strokes were too strong. Most of the work on the game was about this aspect.
Tennis is not my invention, but I believe that the way of recreating it on a computer is unique, nowhere else have I come across it. And in tennis, you don't hit a spherical surface, but a flat one ...
If the players are playing tennis against each other, it is not said that they are playing tennis together ?? I believe that no other entry has a better match to the topic.