Not a stand-your-ground case, never was. Traditional self-defense doctrine.
Martin’s character and past misdeeds and type of person are REALLY relevant here BUT can’t be told to the jury.
Hopefully , they already know about it and can understand that there is reasonable doubt that GZ did not provoke the confrontation.
If the jury believes that Zimmerman provoked it he is in trouble.
I mentioned it the way I did, beginning with the word IF, because it keeps coming up. For a more thorough analysis:
http://legalinsurrection.com/2013/06/zimmerman-case-the-five-principles-of-the-law-of-self-defense/