This game has it all. stealth, action, RPG, adventure, a decent story, beautiful graphics, and great atmosphere. To me, this is the first game of the year contender of 2011 and its set the bar very high.
At one point in the game after playing for a few hours, I sort of came to a bit of a wall. With the upgrades I had chosen and the abilities I was granted, I felt a bit stuck and I decided to play the first few hours again. Normally this would have been a true negative because I would have been bored playing through the first few hours again. But I was not only not bored, I was amazed how much I learned playing through the second time. I was also amazed how much I had missed. And this is one area where this game shines. Even after hours of play, you are still learning new abilities and different ways to tackle each situation they throw at you.
Other than the obvious original Deus Ex, there two other games that popped into my head while playing ; Metal Gear Solid 2 and System Shock. The graphics and many of the stealth elements remind me of MGS2 but done in a way that makes more sense and does not have you looking at the radar the whole time. The art style is also very detailed and clean like MGS2 with very angular components to all the mechanical elements.
On the System Shock side, its mostly the stellar story presentation that Deus Ex manages to put together with emails and the security focus on codes, hacks, turrets, etc. This game manages to take all those elements and mold them into a more modern and better paced game.
The game is also one of the few games that "feels" a bit like a PC game. It lets you save wherever you want (which is very useful) as well as having checkpoint saves. But unlike other PC games brought to the console, this one seems built for the console from the ground up. The controls are excellent and the menu systems are intuitive and quick to use.
I could go on for a long time about all the good things in this game. But I will stop so I can get back to playing.
As far as criticisms, I only have two. The first is that its possible to get pretty well stuck in a pretty awkward path when you don't realize the implications of choices you make. While having choice impact the story and game is a good thing, it can be a bit punishing with no chance of reversal. For me, this happened and I had to re-play a good chunk of the game. But I enjoyed re-playing it and it was my choice so its hard to knock it for that.
The other minor issue is with the camera when you come out of the in-cover view. It takes a bit to get used to it and I constantly wonder if there was a better way to handle the point of view when you leave cover.
Both of these are minor quibbles in a game full of great moments and gameplay. So, go out and play this GOTY contender right now. You will not regret it or my name isn't Pliskin.