Even in the demo it is already slow considering there is only a simple room and no additional sripting like AI.
It is very interesting to see it in the different rendering modes, that way it gives an impression how it could be coded.
I think it is enough to write a fake physics code for such a thing.
The tear-apart thing isn't possible with 3DGS, because it doesn't provide a way how to split a model in others than prefabed models and not arbitrary pieces of polygons.
More interesting is this sort of combination of animations and ragdoll controlled models which already had been posted here before:
http://www.youtube.com/watch?v=3bKphYfUk-M