Exhausting. Late game, the storyline was tedious and tiring. Another escort mission, or another fetch mission. It got to a point where when it would ask me to do something like that, I just turned it off. The first assassin's creed that I didn't even care enough to beat. I cared about it even less than Assassin's Creed III.
Also being on the side of assassins who feel like thugs and criminals, I kept hoping I'd be allowed to go rogue and become a templar (or whatever they're called).
The story is confused, meandering... moreover it's just dull and boring. Make a GOOD game, where I can become a templar. Because these assassins are trash.
EDIT: Why are all of these people flat out lying with a five star review of it! Dear God this is easily the worst AC game ever made. And we've all played Unity. This is worse. I don't want Ubisoft to make another AC game. Let the franchise freaking die if this is the future of it.