I was being semi-factitious, but MASSIVE development? He's slightly nicer to one person, and changes his pricing system. Complete 180. Maybe he would've let that kid die if he didn't pony up the apple, heheh...
He's 98% the same character at the end of the game as he began it. Who knows if what small steps he made will even stick? I hope we never found out.
THE FIGHT WILL CONTINUE, AS LONG AS THE AMERICA INSIDE MY HEART IS STILL ALIVE
^ That's debatable. At the beginning of RE 6, Jake was a cold, uncaring young man who only wanted money. He only put his faith in his own skills and cold hard cash, which never failed him. During chapter 3 of his campaign, he honestly felt that he would become much like his father (insane), and only through his interactions which Sherry did he realize what was truly important. Now, instead of working as a gun for hire for anyone who is willing to pony up lots of dough, he fights Bio-terrorism in 3'rd world countries (where he knows the people can't defend themselves) for apples as payment. Point being, he's now a hero who fights for justice and peace. Pretty substantial character development if you ask me.
When facing a zombie apocalypse, don't join up with a group. Why? Because you'll end up blowing your own head off due to all the pointless drama caused within.