Call of Duty 4's storyline, as might be expected, is ripped from the headlines with a plot that involved Middle Eastern terrorists, renegade Russian generals and a globe trotting setting. The game has you controlling two separate characters; a British SAS operative and a US Marine Sergeant. Each character has a role to play in the single player campaign which takes players on board a cargo ship in the Bering Sea to running house to house in a Middle Eastern urban battlefield and more.
While the Infinity Ward formula is still intact in most of the game they have decided to deviate from the formula a few times. At one point you are in an airplane that's using high powered ammo to take out enemy positions while friendlies are awaiting pick-up. In another sequence (which we won't spoil completely here) you will be doing almost no shooting at all as you and an AI buddy sneak around a location trying to keep out of sight of Russian troops. The storyline for Call of Duty 4 does have a couple of surprises along the way (one of which might be considered controversial by some) but the end result is that the single player campaign looks and feels like a $300M Hollywood action movie.
In most first person shooters you are mostly alone in your fight. In Call of Duty 4, Infinity Ward has done a great job in creating not just clever AI for your enemies but also solid AI for the many teammates you have in the game's sequences. While you don't control them directly you really don't need to; the AI in the game rarely gets in your way. Your pals know when to breach and clear a room and move around to outflank your opponents. Level design, while again mostly linear as in past Call of Duty games, is still solid in this new entry. While you don't have a lot of choices about how to enter a location at least Infinity Ward's designers have made those locations interesting to check out, from the cargo ship to a bombed out Ukrainian city to a countryside in Russia. Health has been simplified in the game; if you are injured, the screen turns progressively more red until you get to cover where you can recover your health in several seconds. It's not realistic and we wonder if perhaps the designers could have found another way to handle the health in the game.
Visually Call of Duty 4 is a treat and while not quite as impressive as Crytek's efforts in Crysis Call of Duty 4's art design, character and weapons models and visual effects are first rate. Infinity Ward has moved away from using id Software's Quake engine tech to their own in-house technology and have created a graphics engine that rivals the looks of the tops engines out there. It's also not a performance hog, either as the game ran very well on my less-than-optimal PC.
However great the single player campaign is (and it is highly entertaining) there is one rather huge issue with it; it's almost criminally short. Most players should be able to blow though the game at normal difficulty in about five to six hours. While completing the game does open up a couple of extra single player challenge and arcade modes, we think most folks will be disappointed that the single player portion wasn't at least a couple of hours longer.