Really looks professional very nice job. The only thing I noticed that may want to rethink is that instead of stopping the physics of a unit after so many spawns, instead you might want to measure the movement of the model, and if it doesn't move much in x amount of time, then you can cease the model, especially considering if a model is still using physics and the only thing moving is his head going back and forth while he lays on the ground, there isn't any real point to it.

Quite frankly this is just a minor point compared to what you have done AMAZING job. Keep it up.