http://www.youtube.com/watch?v=gi60MkXxyfA
Basically what I discovered in the last sequence of the game.
Area Exploit #1
This isn't anything cool or important, I decided to include it just because. When you reach the part where you have to scale a structure to get on the other side turn back and climb the nearby building. Climb to the side and drop when you reach the obstruction that keeps you from going farther. Move to the edge, jump and use the parachute to reach the other side without falling to your death. You are unable to reach the end of the place because of a memory barrier, so the only interesting thing to do is fall below the map at a place that is normally unreachable by a memory barrier when you reach it.
Area Exploit #2
Before you reach Cesare there is spot where guards appear to fall off the structure you're climbing. So what would happen if you reached Cesare without that happening? When you reach that spot instead of climbing up go to the left and move from beam to beam. Then run up the wall of the structure and kick off to the side. You can now reach Cesare, but the scene won't start. All Ezio's attacks go through him, and you can attempt to tackle even though that doesn't seem to affect him at all. So on with starting the scene. Go back and climb down the structure, and the guards will appear to fall off at a certain point, as well as other guards appearing to fight. The scene will start right after that. Now this causes something else to happen: Ezio doesn't appear in the scene to fight Cesare in that area. I've done this more than a few times and I've had Ezio teleport to the area for the scene, but I think I know how to control it. There are two things that seem to prevent you from teleporting to the area: 1. Being in a hanging position. 2. Moving while in the hanging position. After the scene Cesare just stands there. Throwing knives don't do any damage to him, although it does cause him to say a random phrase. Plus the door to the area isn't blocked off by a memory barrier. If you're wondering if this is because the mission is messed up, it isn't. If you go back in the area things will go back to normal: Cesare will fight you, he can take damage, guards will appear to fight you and the door will be blocked off. Now since you aren't trapped in the area go far away. The floor of the area Cesare is in will no longer be modeled in the game, causing Cesare to fall through. He will continue to fall over three hundred meters until he stops. Notice how his health bar is full (probably from being invincible to attacks).
Good job, Aurel. Cesare acting like one of those Disneyland animatronic characters was gosh-darned amusing!