Immerse yourself, you'll love it.
2nd thing you will notice is that its fun as hell and addictive,
i myself suck when it comes to playing single player games for drawn out periods of time, but when i had nothing else to do for 7 hours at the girlfriends when she went to work, this was perfect, i wasn't bored once!
there are masses of enemy's in this game and although all the same looking it doesn't matter to you because all you want to do really is shoot the S*** out of them.
The campaign allows you to play out he war in a time line style, switching your control between Americans, Brits, and Russians.
the levels aren't repetitive at all there is enough new content each level to keep you immersed in the game and wanting to continue.
this game is defiantly worth picking up and having a good spill at it. its fun to play and the game score is rewarding.