I've actually been playing this for the past few days and only finished it today. To be completely honest, I was rather disappointed in it. It started off nicely and I do have some good points about it, however it didn't offer that little quirk that made it stand out from anything else.
I found the Concentration mode annoying. I rarely used it. The story line was mediocre at best. It was all typical and expected. Gameplay was good though whether it was sneaking or blasting people to kingdom come. But what I did love is the scenery. Phew. Standing on top of Eagle mountain and looking down was enough for my agrophobia to kick in.