Call of Duty never has the longest campaigns in the world, but even so, you may be wondering how long Call of Duty:Modern Warfare 4 is, because there is often some disparity from one game to the next. While the story here is a continuation of the Modern Warfare arc, following Captain Price as he’s now on the run after assassinating General Shepherd, you also play as Sierra-1, a squad embroiled in a Korean war.