Silient Night at Emilio's Palazzo
http://www.youtube.com/watch?v=PSeeOdduuSg
Silent Night at Emilio's Palazzo
The goal is to kill every opponent in Emilio's Palazzo without being detected. Just for fun, I also stay entirely unseen in this mission. That means no yellow alert bars over the opponents. Also, no smoke bombs and a minimal throwing knives, just to keep it challenging.
You may need to get the first patch for AC2, which was released December 2009. My PS3 would crash after too many of these "unseen" assassinations. This went away after I ran the patch.
Here are some comments for this video:
0:00 Note that I start with zero Notoriety. Managing Notoriety is important if you want to stay completely unseen throughout the mission.
0:16 Lock onto a guard and back more than 15 m away from him. You can maintain your lock, but he can't see you. You can thus use throwing knives to kill him without detection.
1:23 From what I can tell, you have to reduce Notoriety at some point during the mission to stay completely unseen while killing everyone.
2:25 The archer from the neighboring roof can see you during his patrol. Wait for the right moment to make this kill.
3:09 This archer on a neighboring roof will spot you climbing up the east wall. Unless you kill him first, of course.
4:58 This is the only archer in the mission where can't pull him over the edge. I climb up to assassinate him instead. Note the location of the kill. If I had killed him on the other side of his patrol, the last archer would have spotted me. Killing this archer automatically triggers the cutscene. Now the clock is ticking... You have a limited amount of time to kill all remaining guards before Emilio's boat arrives.
5:35 This archer will spot you during the air assassination unless you've reduced your Notoriety earlier. See comment for 1:23.
5:40 I quickly pick up the archer's body when I notice it sliding off the roof. If the body had fallen down below, it would have attracted the attention of the guards. The Brute on the ground level does not return to his original location upon inspecting a body, which would have made it more difficult to stay completely unseen.
6:00 I move the dead body of the agile so that Emilio does not see it. If he had seen it, he would panic and run around randomly. All guards would also automatically go into Open Conflict, even if they can't see you.
6:57 I take the long way around to reach Emilio so that I can approach from behind.
7:05 I check the mini-map to confirm that Emilio is headed back downstairs. Then I do the final run for the kill.
8:00 Your allies save you from... well... nothing.
Something i will add, may or may not help. After doing that uberto mission where i kill guards before starting the mission, i tried to do the same here and it kinda worked.
At the first part of the mission you must kill 5 archers. Instead of doing that you can kill all guards in the palace without worrying about the cutscene starting. Then when you kill the 5 archers, getting to Emilio is much easier
I am going to try this on Marco, where instead of stealing the golden mask I will kill guards in that carnival first. It seems the dont respawn if you have started the mission, works well with missions that work in 2 stages
We call this "pre-assassinating" the guards. It's something that worked pretty well in AC1. You could sometimes clear out a whole area (e.g. Acre Harbour) before triggering the cutscene that starts the main assassination. After that it was a cake walk. I preferred to strategically take out one or two archers to create an escape path. You don't want to make the assassination too easy. 
Nice video, I really enjoyed watching that.
I'm gonna have to try this when I get home from school.
Your allies save you from... well... nothing.
I enjoy.
That's amazing.
It looks like so much fun, just to do it for the hell of it.
It looks so simplistic and yet I bet it took hours to figure it out.
thx daz! yes, it did take a while to figure it all out. like most of my vids, the execution isnt very difficult... the hard part is figuring out what to do in the first place.