Black Ops 3 is arguably the longest Call of Duty game. Most people report finishing the main story in about nine hours, which is certainly a respectable amount of time for a first-person shooter that releases just about annually.
"Call of Duty: Modern Warfare II" is the most realistic version of the game yet. The first-person shooter game has incorporated methods of photogrammetry and performance capture to transport our world into the world of "Modern Warfare," scanning in everything from Ghost's mask to fully-costumed characters.