I don't know why everyone seems to be making such a big deal about it. I thought it was a really enjoyable game. I played through it, ignored most of the story for what it was worth, and just enjoyed the stealth elements of the game. They were...well, while not excellently done, fairly enjoyable to me at least. Each weapon had it's strengths and weaknesses, and you weren't some multi-talented gun toting superstar from the get-go like most other "stealth" games lead you to become. You have to pick some weapons you like and stick with them, or all of them if you want to just skip the stealth element of it, of course.
The hacking minigames for it were incredibly well thought-out and clever, I hadn't even thought of something like that until they came up with it, and frankly...I like it. It was a great idea. The conversations were a little...one-sided, where it felt like you weren't so much taking part in the conversation as dropping little hints in as to where it might go.
The only thing I had to complain about were a few things, such as: Boss battles. These are the most ridiculous element in any stealth-shooter that someone can come up with. The purpose of a spy is to be stealthy and eliminate someone before they have a chance to do anything about it, not sit through some lengthy boss-battle where their armor regenerates faster than most can recite their first name. The finale was also absolute bullshit. Pitting me (I chose stealth mixed with silenced-pistols and assault rifles, plus tech skills) against a missle-toting helicopter. And don't remind me that this helicopter takes six directs hits from an RPG to bring down.
Sadly, stealth games seem to have this knack for making an explosive finale that absolutely ruins the game for any stealth-minded individual who enjoys...well, stealth! And when you have one of these "explosive finales", it rips any and all stealth elements out of the game and replaces it with run'n'gun. This is not exciting, it's stupid.