Nowhere in the account given by Zimmerman nor in the testimony of Rachel Jenteal did Zimmerman ever identify himself as the neighbourhood watchman. Doing so would have defused the situation and would not have led to Martin's murder. All signs point to Zimmerman as the initiator of the conflict between the two. He did not have to start the fight, and he did not have to pull the trigger. There were ample opportunities for him to withdraw before deciding to kill Martin, ergo the shooting is completely unjustified.
No argument that Zimmerman was amazingly stupid, but nothing that he did was criminal.
There is absolutely no physical or witness evidence that Zimmerman initiated the physical confrontation. All of the evidence indicates that Martin inflicted the physical violence. One witness positively stated that Martin was on top of Zimmerman, the other (much less reliable witness) testified that she thought it might have been Zimmerman (based on the photo she later saw on the news depicting Martin as a 12 - 13 year old).
Zimmerman being an fool is not a crime. Even the prior police calls the prosecution introduced into evidence showed that Zimmerman did not want to physically confront previous suspicious persons, even though he was likely armed then (concealed carry permit obtained in 2009)as he was that night.
The prosecution has nothing but heart-strings. I really don't have a dog in this hunt and couldn't care less what happens to Zimmerman, or anyone else involved in this case; but everything that I have seen presented by the prosecution has been, to me, complete garbage. The judge should have dismissed the case because the prosecution has failed to prove anything.