Basically the professor showed that GZ was taking classes in criminal justice and he knew about Florida law.. in particular self-defense and stand your ground. However, the professor also went along with hypotheticals that could potentially paint GZ as being in "fear" of his life. A smart jury would disregard that but who knows with these people.
There was also a guy that testified GZ took a ride-a-long with a cop and when he requested to do so he listed his reason as wanting to be a police officer. This is pretty big. It shows that GZ was most definitely a wannabe cop.
Lastly the forensics lady showed that the gun was pressed against Trayvon's clothing. To me that shows that GZ's story to the police was false. He said he didn't know if he had shot Trayvon. How would he not know when the gun was pressed right up against his clothing? Also she demonstrated that the gun had a 4.75lb trigger weight.. there was no effort to pull the trigger whatsoever nor was there a safety mechanism on that brand of firearm.
I would say it's been a good day for the prosecution so far but not a complete disaster for the defense..
you forgot the skype disaster. that witness was basically a wash