This was obviously very similar to Call of Duty in gameplay, but surprisingly different in tone. Whereas games like Modern Warfare 2 go all-out with crazy situations and over-the-top action, this game went for a more subdued, but more realistic and subtle approach to the military. Obviously it's still unrealistic in that a single squad takes down hundreds of foes, but at least they don't spawn infinitely. The situations you'll find yourself in are basically hyperboles of real-life ones, which makes you feel like a precise and effective soldier rather than Rambo. Weapons feel FANTASTIC, like they have proper weight behind them as they take down the enemies with animations far superior to CoD's, and the graphics that back up the game manage to make the desert wastelands and large mountain ranges look amazing. Basically, the whole thing is like Call of Duty, but with subtlety and a footing in reality.
I would say the only real downside that I found was when the game took control of the camera from you, instead of allowing you to look around during cutscenes like Call of Duty does. This really takes you out of the game and harms immersion, so I hope they don't resort to this for the next game.
In a sentence:
A more realistic and nuanced take on the Call of Duty formula that is a blast to play through but is over far too quickly.