The Hidden Blade Assassin's Creed in Depth

Still Life - Dynamic Stunt
The target circles around the yard untill he sees something suspicious, at which time he flees to a waypoint on the south side of Palazzo Pitti. This gives a brief opportunity to perform my favorite type of stunt - where both you and the target are running full speed toward the stunt location.

Start the mission by jumping down so that you can poison the Brute. Once poisoned, the Brute will return to his station, which is in view of the target as he does his rounds. Climb back to the top of the roof to wait. When the target sees the poisoned Brute, he will turn and run. By timing your chase appropriately, you can intercept him just before he makes it to his waypoint.

To refine the timing of this stunt, I performed a "dry run" where I started running from a specific location on the roof the instant the target started to flee. I noticed that I landed about 5 meters ahead of him. I then repeated the mission in the same way, except that I waited for the target to run about 5 meters before I started my chase. That attempt was successful, and is what you see here.

Arch Nemesis - There is no Ponte Vecchio
Run away from the target. Eventually, the bridge on which he stands will no longer be modelled in the game. With nothing to stand on, he falls into the Arno River and drowns.

Upward Mobility - 49 Meters
This particular chase path will typically let you escape from pursuers so that you become Anonymous. This gives you a nice opportunity to snipe with the hidden gun, which requires a long period without interruption. Find a relatively high position on the roofs, lock on, and start aiming the pistol. You will lose your lock when the target moves more than 30 meters away, but your aim on the target will be maintained. You will desynchronize at a distance of 50 meters from the target. Hopefully, you'll have a clear shot just before then.

Doomsday - Stunt
This is similar to stabguy's stunt for Doomsday, but it is much easier to set up. It's tempting to jump from the top of the cross, but doing so would result in death.

Hitting the Hay - Literally
This is one of several missions in Bonfire of the Vanities that requires you to remain undetected, which would make a goal of beating up the target seem impossible. Thankfully, the target really hates thieves. Once he is lured away, chase him down, and find a quiet corner where you can beat him up. Don't give him any leeway. If given the chance, he'll continue chasing the thieves instead of engaging with you.

This particular chase path is reproducible, but if the target manages to get away from you, you'll need to be avoid becoming Exposed as you chase him further. If he runs far enough away from his original location, however, the restriction against becoming Exposed is lifted.

Port Authority - Stunt
Start the mission by super/hyperblending, which allows you to avoid detection as you climb up to the mast "top," which is the platform that appears similar to a crow's nest. From here, you can perform a stunt jump to the deck near the bow, so you'll need to lure the main target to that location with a dead body.

As you climb up the rope ladder, be sure to lock onto the guard at the bow of the ship. Shoot this guard when you reach the top. The main target is too far away to notice this dead body, so you'll need to shoot another guard in order to lure the target to the bow. As the target follows the trail of dead bodies, walk below the lower end of the jackyard and jump straight up. Pull yourself up and walk to the end of the jackyard for the stunt jump. Aim carefully between the mast and rigging to avoid bumping into them.

It's possible to perform a stunt assassination from a greater height if you are willing to bump into parts of the ship as you fall. I dislike the appearance of such stunts, so I don't show them here.

Port Authority - Top-to-deck Stunt
If you find it difficult to aim the previous stunt, you can jump from the top instead. The aim for this jump does not need to be as precise.

Port Authority - Top-to-pier Stunt
You can perform a stunt jump from the top to the pier below. The falling distance from this stunt is essentially the same as the one from the jackyard to the deck. Unfortunately, this stunt is a pain to set up, as there are numerous dead bodies needed to lure the target to the correct spot. I skip showing the set up for this mission, as it is quite lengthy.