Stunningly tedious after the first hour
Don't get me wrong - for the first hour when you're learning the ropes and doing your first assasination mission, it nees new and quite exciting, despite some obvious flaws (I'm looking at you, hideously clunky combat system...). But after that...well, you have to do EXACTLY the same thing eight more times. And that's it. The whole nine missions of the game are essentially exactly the same thing - complete 3 inane 'information gathering' tasks that have absolutely no bearing on the final assasination (you'd think that info saying 'The target will be on his balcony...' would be a setup for a good bit of planning witha crossbow, but no...), then you walk up to your target, listen to five minutes of pseudo-philosophical ethics churned out by someone not quite as close to death as you may have hoped, then repeat. Again. And Again. And again and again and again.
It'd be forgivable if the 'free running' thing was exciting, but it isn't. It's like a badly arranged racing game and that's about as much as you can say really. To put it in context - I played for eight and a half hours, shouting and swearing at the clunky evade controls every mission, and suddenly toward the end of the Eighth one it suddenly occured to me "WHy the hell am I still playing this??? I'm not enjoying it, it's boring me senseless, and clearly it's only bloody-mindedness to get to the end that's keeping me going!!!". And I've not touched it since.
So - not a bad game as such, just stunningly tedious and the most repetative thing I've played since Horace Goes Skiing back in 1982.
Avoid. Spend your money on something more interesting. Like a tin of paint to watch drying, for example.