Game is decent enough, gameplay is fun (if lacking in variety), graphics aren't that bad, but not the best I have seen, not really noticed any music but most sound effects are decent, voice acting is kind of bad however.
Main problem with the game if you ask me is it is kind of short and easy, and the side missions are all really dumb and a waste of time (run from point A, to B to C in the shortest time possible!!!). Story line is not that great either.
Also, the AI for enemies in the game is really dumb, and relies on a lot of cheap tricks.
Enemies appear literally out of thin air, and if alerted will keep constantly respawning
Enemies also make way to much use of calling strike teams, and there is literally a type of enemy whose only purpose is to call strike teams (it also happens to move stupidly fast, is stupidly small and can fly around). As the game goes on, strike teams are called more and more often, and it is usually impossible to stop them from being called. Strike teams are overly persistent (can literally follow you across the entire map), and can even call other strike teams, and if you have one of these floating enemies following you (again stupidly persistant) it will call another strike team as soon as you destroy one.
Enemies are also stupidly reckless, especially strike teams. Plenty of times I have failed a mission because someone called a strike team, which spawned 2 helicopters, each of which proceeded to shoot out missiles like they were firing a machinegun, which killed a target I had to absorb. It is almost like these army guys don't care who they kill, or how much damage they do, they will rain missiles down on you like hell fire.
Although enemies are highly persistant, they are also really stupid for some reason. If they lose line of sight of you and you use a disguise, they lose you and retreat. Even if you are on top of a skyscraper and they saw you running up it and you are the only person on top of it, hell, if they wont even notice it is you even if you jump off the skyscraper and glide right past them.
Other than the short length of the game, and the dumb AI, it is a fairly decent game. I'd say rent it though, don't bother buying it.