Alright, here's what I have to say about the game itself. I liked the gameplay. I thought it worked really well. The gun mechanics were a little strange when it came to things like pistols dealing more or less damage because your just better with them (I'm still shooting the guy in the fricken head). The main problem I had with the mechanics was the difference between killing someone and knocking them out. Other than a feeling of superiority there really isn't any difference in the game if you massacre the people or just stun them into oblivion. Of course there is the totally non-violent stealth way of just running by everyone but that doesn't work 100%. I just thought the game's whole "you don't have to kill anyone" aspect would be a bit deeper. That said I have to say the game has better level design than any game I've played to date.
But this all leads me to the game's big flaw. Its story is fairly mediocre. A thrilling tale of conspiracy doesn't really do it for me when there isn't really a hell of a lot of depth to the conspiracy. Especially when the story seems only to be something to drive forward gameplay as opposed to being something that does both advance the game and create something interesting. For a game so widely celebrated for being deep I found it disappointingly shallow. The endings could have been better executed than a few lines of dialogue and some text, as well.
All in all, good game with a mediocre story.