Thanks to Call of Duty: Black Ops II, there are now 14 games in the Call of Duty series.
I could talk for hours about why this iteration of Call of Duty is different than the previous 13, but here's one reason:
Composer Jack Wall.
The score to Black Ops II reflects the different decades in which we play as players. Areas of the game set in the 80s tend to focus more on orchestral sounds. And, while the orchestra is present through the majority of the soundtrack, that symphonic sound fades more into the background if we're playing a level in the year 2025.
Jack blended the organic strings quite well with electronic elements, particularly in a piece called "Rare Earth Elements" (especially at about :39 into the track).
But for me, the musical raison d'être comes during a piece called "Cordis Die" in a scene where the player joins the antagonist up on a courtyard stage to address his people. The player walks alongside Raul Menendez (bad guy but multidimensionally so) through the halls of a building, leading to a set of double doors that open into the courtyard. The second those doors open (1:07 into the track), Jack hits us with the roar of the ensemble with the most incredible, weighty, significant march that literally made me pause the game to make note of the scene.
Jack explains his thought process behind "Cordis Die" and the rest of the music on the Black Ops II soundtrack on the latest episode of Top Score from Classical MPR. Also on iTunes.