A collection of discoveries that by themselves do not warrant a video.
Catching Up with Charles Lee
In the race against Charles Lee, the game will stop him at certain points to let you get close. You can get ahead of him by climbing the route shown in the video. At a certain point you can get right by him without further triggering the chase. The target is invincible to attacks, so I have yet a way to assassinate him early.
Fast Travel Glitch
I noticed this happen when I left playing as Connor and started a game as Haytham. In the Frontier, the fast travel icons for New York and the Homestead (which Haytham never has access to) appear. Fast traveling to the Homestead has you run into an invisible barrier, but going to New York spawns you past a memory wall, desynching you instantly.
Area Exploit at the Opera House
You are able to skip a checkpoint backstage, the one where Haytham nearly falls from a hanging prop. This will prevent you from progressing any further in the mission. I found you can get to these two high beams near the ceiling, but not much else to do with this. Currently no way to get off the stage without failing the mission by "disturbing the play".
The Phantom Weapon
In the memory Infiltrating Southgate, one of your men at one point drops his bayonet and pulls out an iron tomahawk. After reaching the fort, you can still see the weapon floating in the air. I've seen weapons drop when characters despawn but was unable to pick it up. Just to make sure, I tried to get a guard to pick it up, but the game doesn't seem to register the weapon as dropped.
It's funny how in the Charles Lee scene there's visible geometry without collision detection (the beam through the head) whereas at the Opera House there is invisible geometry that you can climb on. Typical video game.
It's funny how in the Charles Lee scene there's visible geometry without collision detection (the beam through the head).
If you are referring to 1:27, that is meant to collapse during the chase. Some of the architecture in the ship doesn't appear until the mission is ready to start.