The Hidden Blade Assassin's Creed in Depth

Turn targets into one-hit punching bags!
Read this description for the explanations of how each target was set up, as well as why other targets couldn't be killed this way.

Tamir

You can't take his heath down early without getting detected, which makes it impossible to progress.

Garnier

Get into the hospital early through the window.
http://thehiddenblade.com/garnier-easy-way-preassassination
Then take down his health until he's one punch away from death.

Talal

After killing his guards, take out Talal's health with throwing knives.
http://thehiddenblade.com/air-assassinate-same-height
You'll need to have done the Garnier assassination first to have the knives unlocked.
Now one punch is all you need to take him out, but it's easy to miss on the running target.

William

Get into his fortress early.
http://thehiddenblade.com/williams-instant-kills-and-king-richards-death
After punching him nearly to death start the scene. Afterward sneak up on him with a jump. If you get detected, William will get into combat stance and block the punch, which happened a lot until I jumped from the spot in the video.

Note: Aurel found this first and then told me about it, so I didn't really do anything.
You can do this by starting the William assassination at the bureau and then infiltrating the fortress without the scene starting (see this article). At certain points in the fortress, all the soldiers will disappear. You can then setup an 'invisible kill' with air-to-assassinate: you lock onto your target and make sure you jump through one of these spots. Near the back of the group is a great spot.
Altaïr then performs an air-assassination ( ) and the memory corridor scene starts. Afterwards, you can just stroll out of the area and get back to the bureau, after which you will have completed the mission.
I opted to get out of the city instead, to see if the back-to-the-future exploit worked. It didn't, but William's army has become substantially smaller, which makes setting up an anonymous kill very easy with a couple of knives.

Finally got around to doing this. The goal is to escape while inside the fortress. This is a pretty robust route, always works for me. There are other hiding spots inside the fortress should anyone else want to try this.

Ian and stabguy pretty much nailed all the stunts for this assassination, so I thought I would take a different approach. Use the priests so you can blend right next to him and assassinate him in front of all his guards.

For those interested I will start working on the save citizen video for this district soon

https://www.youtube.com/watch?v=X31O38Jpyw0
[Front-paged - stabguy]

A superfast blitz on William is possible because of how the game works. When you get to the assassination jump from a certain spot on a roof to grasp the edge of a railing and pull yourself up. The scene won't start because you're not in an upright position. Jump from railing to railing and other structures to get near the gate entrance of the citadel. When you reach this destination and Altair is standing the scene will start and you are in the huddle of William, King Richard, and other soldiers. You can now walk inside the citadel to where William will appear after the scene. The camera view will focus on the scene outside, so steering your way in there can be tricky. You'll know if you've reached the target's room because there are two guards posted on either side of the entrance outside of it. Stand behind the table on the far side of the room and wait for William to appear by it after the scene ends, mashing the assassinate button. You know what happens next- William gets owned!!!