A nice little trick I found in this video is to combine poison and the arrow storm. You can gather loads of guards into one spot and take them out all at once. You can also get on top of the aqueduct without needing to renovate that area by using the parachute.
During the daytime one of the save citizens appears where he shouldn't, in the restricted area. If the captain walks past them, he will never see you or react to you.
I didn't know that Ezio was also a descendant of Jesus Christ, as he can now walk on water through the skin of his descendant!
I'm assuming that the amount of kills relating to Arrow Storm is related to how close each guard is to each other in their vicinity. You've clearly demostrated that with your tactical use of poison dart Arrow Storm!
Also, at 5:35, that would be probably the longest jump Ezio made for a horseback assassination. I'm not sure what he eats to keep up those leg muscles, but he did cover a LOT of distance.
0:48. Well, that's just cheating.
Also, I had a big WTF moment at the end.