The Hidden Blade Assassin's Creed in Depth

This video demonstrates a weird glitch with AC2 that allows you to finish the Francesco Salviati without killing him, and without the post-assassination cutscene.
At the end of the mission, Francesco simply vanishes in thin air, and the mission is complete.

Here are the details:
1) Start by breaching the compound walls. The first time you breach the compound, the game will despawn the mercenaries that you started with. No worries, just leave the compound and get some more mercenaries. While you are at it, leave the area so that the front gate is despawned. The gate will not respawn when you return.

2) Send the mercs to attack Francesco inside the compound while you remain undetected. Once the mercs attack, I believe Francesco is programmed to target you. But since he cant' find you, there's a waypoint separation, and he becomes unresponsive.

3) I had intentionally chosen a small group of mercs to attack the compound so that they would lose the battle. When the last of the mercs dies, Francesco vanishes, and the mission ends without a cutscene.