The articles linked to deadspin say there's video of them hitting each other with their hands. Who knows, really, what those videos show - but if they show that it's likely they'll show who was the initial physical aggressor. (Also, no info on whether either had been drinking.)
It looks like she's conscious by the end. Oddly enough, unconsciousness is not usually seen as an "injury" which makes a simple battery more severe. (Felony battery is usually something done with a weapon, or which results in a scar or serious physical injury. Formulations vary from state to state.)
What's really weird is the security guard's response. You think he'd go over to see if she was breathing. He just kinds of stands around though.