Normally when you perform an "Arrow Storm" attack in-game, it kills all guards within the boundary of your monitor's resolution (i believe). It's kinda funny that even though Ezio used that attack during the introduction scene, it didn't nail Cesare in the process. :\
That aside, again you've done amazing work! Ezio's confident smirk... that's why he's my favorite Assassin! Uh... ignore the fact that my avatar is that of an angry Borgia guard.