Great game that needed some polishing to be spectacular.
The graphics are good, sound is good, and physics is alright, but the physics can be extremely unrealistic at times. This is only a minor drawback, but it is still noticeable.
I was not impressed by the storyline. I was actually very confused by it. I imagine that this is because I didn't play the original Dues Ex, but I am disappointed that at the end of the game I still didn't really know what I was fighting for. The multiple endings are kinda interesting, but nothing more. They really don't show much of anything, so they were a bit disappointing. I was also disappointed at the ease of changing the ending (I simply saved at the beginning of the last level and replayed it 4 times for the different endings). The factions are set up in such a way that you are supposed to be faced with difficult moral decisions (or at least that was what it seemed the developers were going for), but since you can change factions at any point in the game right up to the last level, there really isn't any kind of decision. Personally, I found the factions to be more annoying than anything. There was so much effort put into each faction trying to recruit you that the story was completely lost. By the end of the game, I knew everyone was trying to use me for something, but still couldn't figure out what.
Ultimately, since you can just replay the final level to get all the different endings, there isn't a lot of replayability. I have played through the game completely twice, but I had to wait about a year between games because it just isn't a game that draws you back to it. It is a great game in a lot of ways, and it is fun to play through, I recommend getting this (I've seen used copies for $5 at EB Games). It would also be a good game to rent, since it isn't a game that you're likely to want to play over and over and over.