Yes. It is true that the law of reflection is only an approximation of what really happened!
The effect of rubber and the spining effect also can be simulated
if we know the spring constant and apply conservation of momentum,
energy and angular momentum. But that would be too complicate to
the students who just learn physics.
The purpose of our animation is for teaching. That is why I
simplify the problem and the result are still very similar to what
really happened. Thank you for your comments. Could I add your comments to the end of the web pages?
Regards!