Played Call of Duty: Modern Warfare to the finish last week, and MW2 this weekend. Here are my thoughts, as spoiler-free as possible.
It was lovely to look at, with graphics way beyond the first incarnation of the game. The modern equipment options (night vision, claymores, flash-bang grenades, grenade launchers) gave a few more tactical options and experiences. I thought that they've come on a long way in breaking up the fps which makes up most of the game with different types of gameplay. The gunnery or tank-driving levels of the first few CoDs now look very clunky and arcade-like. Now, gunnery from helicopters during assaults, or the unexpected chase scenes, come much more seamlessly into the action, and calling in and guiding Predator drone attacks or providing air support as a C130 gunship operator is part of the mission, with the very different visuals via gun cameras etc a nice contrast with the photo-realistic scenes on the ground. The stealth and sniping levels are a lot of fun, too. Something else they do well is throw in a brief mini-game here and there to climb up a cliff using ice axes or similar, so it isn't all walk and shoot. This is particularly well-used at key parts of the campaign story. The jump mechanic to clear low obstacles is used well in some of the chases and escapes, but actually added to my frustration where it doesn't work because you're reached the edge of the playable area. A few times, I thought "I could flank them, if only I were able to climb over this three-foot high trestle...".
I did find that there's much less incentive to drop whatever weapons you're issued with and pick up enemy kit than there ever used to be. Any modern assault rifle's worth having, and there are only a few situations where I swapped my kit for something I found during a level. I picked up a mini-Uzi instead of the pistol to get the best speed plus firepower when running and suppressing attacks from nearby enemies, and had occasion to seek out something with iron sights at one point. Some of the weapons you can pick up, and especially a few of the ones unlocked by completing the campaign, do seem geared to shoot-'em-up deathmatch players. I'm thinking about the Desert Eagles, .44 magnum, and the "ranger" twin sawn-off shotguns in particular. Along with the riot shield.
Ah, the riot shield. How I hated it. Makes crouching enemies invulnerable to frontal attack while they're facing you. Including firing RPGs and grenades at them, or heavy bursts of machine gun fire. There are tactics to defeat them - flank them, lob cooked grenades over their heads - but they're hard to beat. And doubly annoying, as I just don't buy them as plausible kit. I've always loved the CoD games for their reasonable AI and a design that encourages sensible behaviour in combat. Riot shield users are typical video-game enemies, taking things further away from any kind of realism. As are the dogs. I didn't mind the dogs in the first of these games, especially the ones in Pripyat. They were there to be avoided on a stealth level, and made sense in that context - as do guard dog patrols in MW2. But the attack dogs you get set upon by at various stages are a real pain. They're popular as a perk in deathmatch, though, along with the riot shield, shotguns, heavy calibre pistols and the like. It's just not the kind of gameplay I like.
The story that the games chose to tell was interesting. Mainly in the second game, but starting with the first, there is a subversion of the line I'd have expected. In fact, I only decided to give them a look when I realised that they weren't a celebration of the heroic victory against Saddam and his WMDs, or a "do we get to win this time?" Rambo fantasy. I think a lot of people will play it in that style, if they think at all about the content, but it is in fact telling a rather different story. And it does that quite well.
The old WWII incarnations introduced the multiple-character element - you played as a Russian, an American and a British guy at different stages of the games, all Allied soldiers fighting the Nazis. Which is a clear, unambiguous good-vs-evil background you didn't have to worry about. I for one preferred the larger-scale operations to the special forces missions.
In the modern era games, special forces come to the fore. But this is OK, as these games are structured differently. It's not your personal "walk on part in a war", it's an unfolding thriller in which you take part as it develops. The headlining meme comes from Ramirez, a US Ranger you play in several missions. It's a familiar feeling to players of the WWII games - you're constantly being barked at by your superiors to give covering fire, snipe at the MGs, capture those mortar pits, blow up that tank, get back and man a field gun, etc etc. Ramirez gets most of the conventional ground-fighting action, so he gets more of this treatment than most MW PCs. It's not that the SAS and Recon Marines don't have plenty of instructions to follow, it's that their levels tend to take place in an environment more like an Alistair MacLean thriller than a full-scale war. There's more plot to what happens - it's more an action movie than a war film. Sometimes the designers railroad you into this - you reach a checkpoint and promptly fall off a roof, or something, then you have to scramble to safety with seconds to spare. Those mini-games often come into their own here. Your orders make sense in terms of fast-paced narrative sequences - "the bridge is down! Rappel down and swim for it!" - rather than sounding like your sergeant just hates your guts and wants to get you killed.
The extent to which some of the missions have a narrative of their own has really come on. I'd single out the Chernobyl sniper levels, the North Sea Hijack action sequence, a lovely echo of storming the Reichstag in the original CoD, and the atmospheric chases through the favela.
The multiple-character aspect mentioned above really gets used well in these games. Both in use of NPCs - characters from the first recur in the second, with significant roles to play - and in giving the player a stake in the big story. The different characters are all involved in key parts of the big picture, and the game uses that to involve you in it and make you care about them. And the story isn't meant to be a cosy, or straightforward, one. The world is dark, and morality is often grey. The bad guys are very bad, and you do get to save the world in the first one, but it gets worse by the second. Both games have deliberately shocking moments, and neither are truly "hooray for our side". The ending is satisfying, but still bleak.