Don't compare it to COD.
First of all lets talk about price. It's a total ripoff that you can get this game from gamespot for $9.99. OMG $9.99 that's unbelievable. When I bought this game I couldn't believe the price lol I was looking for the catch.
The gameplay is great slightly different than COD. There is a lean an peak system in this game. When you use the iron sights or scopes you can tilt the left thumb stick to lean to the left or right around cover (can also do this with k&mouse) The post processing is great. It gives you a nice blur when you run or moving very fast. It seems like there is always a target or something to blow up to complete your mission and just when you think you're done lol something else opens up for you to destroy or take control of lol. COD doesn't offer these things.
I like the fact that you constantly upgrade your guns through the single player campaign and you get more points by getting head shots. This is yet again something else COD DOESN'T HAVE. Only in multiplayer you can upgrade your weapons, but it's not by headshots its only by meeting challenges or gaining points. You have to earn upgrades in this game even in the single player.
All in all I would say this game didn't get the score that it should have gotten because of the huge shadow of Call of Duty. This game offers some things that make you say... "Hmmmm, I wonder why they didn't put that in Call of Duty"? Its a great game and it's optimized great for PC. For $9.99 it would be a sin not to purchase this game.