If you watched E3, you will recognize some of the footage here, but the video fill in the gaps between/after. For those who have not, this is a great look at B:AC. It is also about twelve minutes long, so be ready to settle down. There aren't any spoilers, but if you want to keep this game a surprise, I would not watch it.
But I did and it made me all the more excited for this game. Can't wait.