The Hidden Blade Assassin's Creed in Depth

This is very similar to a previous video:
http://www.thehiddenblade.com/stunt-assassination-dante-moro-and-eagle-s...

Dante and Silvio start running from you once you cross the threshold to l'Arsenale. So don't. Go over the walls instead, and you'll find your targets as (mostly) unresponsive puppets.

http://www.youtube.com/watch?v=A7Nces5P3rw

The goal is to shoot Dante Moro and Silvio Barbarigo from as far away as possible. This mission relies on the unusual mechanics of the hidden gun. You need to be within 15 m to lock onto a target. Once locked on, you can maintain that lock if you remain within 30 m. If you start to aim the gun at your target while you are locked on, you will be able to maintain your aim. The shot will hit its mark as long as nothing obstructs the path of the bullet, regardless of how far the target travels from you.

Anonymous Blitz
If you don't enter l'Arsenale, you will stay Anonymous and the targets won't move past their first waypoint. This is the perfect opportunity to kill them with throwing knives. They will be too far away to lock onto, so you'll have to aim "manually." Throwing knives travel in the direction of your last horizontal movement. Walk in the direction you would like to aim, and look over Ezio's head to fine tune your aim.