The other big FPS that came out in 2007 was Call of Duty 4. It aimed to give Halo a run for its money, and as far as many people are concerned, it did just that. It follows the same formula as Call of Duty 2, in that you play one person from different theaters of war. This time, however, instead of being set in World War II, you're in the not-too-distant future in the Middle East and Russia. Your mission is to stop a radical group from taking control of a Middle Eastern government.
Towards the beginning of the game, you play the part of the Middle Eastern president being overthrown. You are taken captive, driven to an auditorium, and executed. I say you "play the part" because you do actually have control. Granted, all you can do is look around, but it brings you into the story in a way that a simple cutscene could never do, even if that cutscene was rendered in first-person.
Gameplay is pretty traditional Call of Duty fare. You're a member of a squad, and you have some mission to complete, which usually involves just getting from point A to point B. Your squad generally stays with you, waiting for you to lead the charge (which feels just as odd as before — you're not the highest rank on the field, because you're getting your orders from others, but the squad refuses to advance without you). Enemies shoot down at you, and in most cases infinitely respawn until you move forward enough to trigger their "stop spawning" directive. This leads to some very frustrating moments, as you're forced to move forward into fire, and nothing you can do as far as shooting the enemy will lessen their numbers and the fire raining down on you.
The story is fairly intense. The Middle Eastern ultranationalists get a hold of a nuclear weapon and threaten to detonate it. Their supplier is a Russian arms dealer, believed to be killed 15 years ago by the man who is your commanding officer in the British missions. Along the way, you'll piss off the arms dealer, and he'll launch three nuclear missiles at the U.S.A., and you'll have to plow through a missile complex to get to the control room and stop the missiles.
Spoilers appear in the next paragraph.
The game flows pretty smoothly from action to story, so much so that when the story took a negative turn, I was afraid it was because I had made a mistake. One such moment was when the nuke went off in the Middle East. Your team doesn't get away in time. I thought maybe it was a consequence of how much trouble I had on the previous mission, if I had been just a bit faster, would my team still be alive? Almost as if to drive home the point, the other "immersive cutscene" happens here, when you get to crawl out of the wreckage of your chopper and stumble around in the aftermath of a nuclear explosion, before you succumb to your injuries and the radiation and die. It's a very disturbing moment, as without any direction, you're confused and disoriented, and you can't do anything but fight your body as it drops to its knees and your vision blurs, and look around you at the desolation, with the mushroom cloud in the distance. That scene haunted my consciousness for days afterward.
Of course, there are a set of achievements for completing the game on the Veteran difficulty. This is an exercise in self control and discipline, as many times I wanted to throw my controller through something (I was in debate as to whether the TV or the window would be an appropriate target). The infinitely-respawning enemies seem to shoot with uncanny accuracy at amazing distances, even while at a dead run. They also seem to be able to withstand gunshots, grenades, and, often, air strikes in their quest to eliminate the most important Private/Sergeant the British/American armed forces have ever known. While most of the time it's an exercise in patience, there are three levels in particular where you are timed, so waiting for an appropriate time to move isn't an option. It is these levels, where you are forced to push yourself into death time and time again, that cause the most frustration. Google for "Heat", "No Fighting in the War Room", and "Mile High Club" in conjunction with "Call of Duty" and "Veteran", and you'll see what I mean.
Multiplayer is an all-new experience. You can "build" your player from a set of weapons and "perks", saving a few different combinations to pick from for a battle. Initially, your choices are small, but as you progress, you earn experience points and level up, unlocking new weapons and perks. It's a very flexible system that lets you decide how you want to play it, but it does take a lot of thought, experimenting with different weapons, deciding what would be best on what map. Internet discussions abound over which weapons do best with which perks, the benefits and consequences of putting a silencer on certain weapons, and many more things I can't even begin to describe.
I like the concept, however I do find it much more difficult. I don't have tons of time for gaming, and the time I do have, I don't devote a lot of it analyzing weapons and trying to come up with the best combinations. It means it's a lot harder for me to just "pick up and play", and as such, I haven't picked it up and played a ton of multiplayer. As such, I have not unlocked as many weapons and perks, and that puts me at a disadvantage. Yes, on any given day, a level 1 player with the default weapons could take out a level 50 player. However, because that level 50 player is likely to have 3 grenades, two primary weapons, a silencer, a radar jammer, and/or who knows what else, it's still going to be very lopsided in favor of the player with more experience, no matter what his actual skill level is.
One thing that thoroughly annoys me about multiplayer is the rewards for killing streaks. If you get three kills in a row, you can call in a UAV to pinpoint enemy troops. 5 in a row grants you an air strike, and 7 in a row calls in a chopper. I cannot count how many times I've died to air strikes and choppers. I've had many times where a chopper would gun me down, I would respawn, and there that chopper would be again. It is the ultimate in helping those who don't need the help. I honestly don't know how anyone could feel good about having a chopper do all their killing for them anyway, especially when they were doing just fine without. It's cheap and unfair, and I'm not just saying that because I'm usually on the receiving end of the shaft.
The party system leaves a lot to be desired as well. The game seems designed around the concept of "keep playing", trying to flow you from one match into the next. The big problem is, if you want to back out to the lobby with your party, you each have to do that individually, and only if your party leader backs out, too, will you still be in a party. Plus, if you are in a lobby and the party leader has to leave, that's it. Party's over. You have to recreate a room, because there's no way to transfer ownership of the party or have the room persist when the leader leaves. "Why can't it be more like Halo?"
In summary, Call of Duty 4 has a great single player. The multiplayer component is harder to get into, but it has a large variety of maps and game types to keep things interesting.