To clear things up: I do like the story. It's amazing, original (as far as I know) and very very interesting. The music? Awesome, very fitting and well made.
Now that you've read the good parts, I'll say what in my opinion is a game changing flaw: the actual gameplay. You'd think that controlling an assassin and jumping from building to building and climbing walls and assassinating targets and sneaking around would have been tough, right? Wrong. Not only that, but in combat you could hypothetically face millions of enemies and fight them off. How? Because they charge you two at a time max, and even then you can counter attack them. In my opinion, that makes the game completely unchallenging, thus boring, and it makes it more of a movie than a game