Remind me to be wary of bad reviews in the future. I got this thinking it would be a bad filler title between better rentals, but this ended up being one of my favorite stealth action RPGs this generation, right up there with Deus Ex: Human Revolution. If you like Mass Effect, the Fallout series and The Walking Dead, you'll like this a lot.
I played through twice, the first time at 30 hours and I loved it. Then you can play it again with different choices (like kill everyone) and you get almost a completely different storyline and character reactions. It puts Mass Effect to shame. There are achievements and in-game rewards for being nice or nasty to people.
The opening Saudi levels are kind of blah, but once you get your first safehouse, the excellent plot and characterization kick in. There are dialogue choices throughout and you really have to be on your toes.
You can do the Moscow, Taipei, or Rome levels in any order, and also the order you do them affects the storyline and character interactions. One guy will get offended if you do a bunch of Taipei missions before meeting him and he may betray you.
The dialogue choices and even how you play levels (stealthily or killing people) affect how characters react to you later in the game. It also affects the kinds of perks you get (faster cooldown, higher pistol damage, etc). You never really get punished in terms of perks, even offending your handler can give you a positive one.
It does get knocked off points for clunky combat. It's not tight and focused like in Deus Ex: HR. You have to put points in your gun skills to get a good shot, I think that's what a lot of bad reviewers didn't understand. I focused on a pistol/stealth build and I did fine. Also, you can't hide bodies and they disappear off the ground after a minute, which is poor.
The graphics are serviceable, certainly not awe-inspiring like say Hitman: Absolution. Don't let the minuses dissuade you. This is a great game!