The Hidden Blade Assassin's Creed in Depth

Early Death
When you first start chasing after Charles Vane he appears at a view point. The mission is scripted to make him escape before reaching him, however they overlooked the fact that you still have a throwing knife available. by climbing to the spot shown in the video you can knife him without activating the next checkpoint. Killing him has no effect on the mission, and you continue as usual.

Early Death 2.0
During part when Charles shoots from a log you can also knife him, causing him to disappear (counts as a kill in stats) and activating the next checkpoint.

Use of Poison
Normally you can't use poison with the blowpipe gone during the mission and no ammo. However after crafting a dart you can counter tool with it.

Blitz
Another time the throwing knife comes in handy. To avoid his gunshot run behind a ruined wall and proceed to a part of the building you can climb up to (ironically located by a scaffold the target collapses to prevent you from getting up there). When you get in range knife him.

Different Spawn Point
If you restart the last checkpoint after the memory corridor you spawn at pretty much the same place during the assassination that you would during the scene post memory corridor.

Deathly Fear of Heights
If Charles Vane falls off the edge of the roof he's standing on, the memory corridor triggers before he even hits the ground and despite the short height. Purposely done by the devs.

Unexplained Death
Same concept as the previous kill. Leading the target to a certain spot triggers the memory corridor because the game thinks he "fell'.

Eagle Strike
Get the target to pursue you to ground level and climb up the building. He'll search for you by the stalking zones, one of which is close to where you need him to be for the eagle strike. This could take several tries. You don't want him to be too close or he might detect you and block the air kill.

Attempted Human Bait
Two types of predatory animals are present in this place. I was hoping to get them to kill the target, but they don't go after him like they do with normal guards. Must be an AI thing.