2/3 of this game are really fun.
Onto the campaign. It was actually quite fun. The campaign does a pretty good job of balancing the typical shoot, run for cover to heal, and shoot some more tactics with vehicle, drone, and emplacement parts to the game. The story is a little weak as expected, but of all the games in the MW series, it is the strongest and does a pretty good job of wrapping up the story arc.
Now to the Coop, another feather in Infinity Ward's cap. In this round of the MW series, we get a survival mode that we're starting to expect with other shooters in addition to the typical mission modes. There's a lot of depth here. In survival mode, instead of simply making waves of enemies stronger and stronger, the enemies adopt new guns, new armor, and new tactics, while it has it's own leveling system that provides access to better guns and equipment. Combine this with a nice variety of missions and you've got another third of the game that's quite fresh and fun.
And finally, there's the multiplayer, and sadly this is the glaring weak point in the game. On the surface, you have a multiplayer design that's more of the same, new levels, new but similar guns...basically a fresh coat of wax on MW2. Infinity Ward seemingly attempted to make it easier on newer players by offering a different kinds of killsteak system that uses your point total to reward you with nice, albeit weaker, killstreak rewards than that of the typical systems. They also added perks that seem to favor newer players.
But here is where this strategy fails immensely. IW went too far and made the multiplayer even more of a campers paradise that the previous games. There are so many nooks and crannies, so many cheap tactics, so many cheap ways to kill/die, that it actually makes less sense to actually move around the map than it does to find a cozy spot, light a fire, roast some marshmallows and wait for the next unsuspecting victim to walk by.
Couple this with massive amounts of lag and an inexplicable lack of options for finding matches closer to you and you're left with a multiplayer experience that's just not fun and even frustrating. It's a shame because multiplayer is typically the Call of Duty bread and butter. I wanted to enjoy this game, but really I could only enjoy 2/3 of it, so in my mind, it deserves 2/3 of a score.