I suppose now is a little late for me to add my impressions, but I just got the game a few weeks ago.
I played the campaign on Normal since I'm a baby and COD2 veteran nearly cost me a controller and a new television through frustration. I was convinced I would not let that happen again. All up the game provided a good fun challenge at this difficultly, though I'd hate to try it on anything harder. It really does drop you into some tough situations, such as the part where you've just grabbed the rocket-launcher from the barn and blew up two tanks just as the sun was coming up. Trying to fight your way back through the infinite waves of enemies while under a time limit took about a dozen tries. The open-spaces were a great mix-up, reminding me of all the good parts of Halo - do you run straight through the middle, or do you shy around the edge, picking people off, or do you crawl through the pipe after clearing it with grenades? That's something too many games lack thanks to the "corridor shooter" genre that FPS's have largely morphed to.
Graphically the game does look pretty special - being "600p" didn't seem to hurt the game's look as much as Halo's "640p" did, which was a little surprising. My girlfriend commented that the game was one of the nicer looking that I've played, which is always a good sign to me.
I loved the night-vision sequences, especially when you're sneaking into a dark house. Gorgeous! You walk in and silently kill someone that doesn't even know you're there. Absolutely cracking gameplay. I was hugely let down later in the game when you are doing house-to-house walks at night, but you can't shoot out the lights. Terrible, terrible design. I could do that in the first Splinter Cell... surely in 2008 we can add this as a staple to every game, especially when you've teased me with the earlier great night-vision missions.
The sniper mission was pure gold, too. Probably the stand-out of the whole experience for me, with the whole "sneak" mechanic making me feel like a true bad-ass. Give me more of that.
I was personally creeped out by the mission where you're in a plane/chopper taking out people remotely. A little too close to reality personally, and not something I'm entirely comfortable with, though that's probably the point.
I found a lot of people gushing over the cinematic elements, such as the opening sequence with the President, and the nuke scene. They were a little shocking, but overall I honestly didn't relate too much. Maybe it's just me, but any attempt to align me to my character seemed "missing". I actually thought COD2 implemented the idea of "characters" a little better.
Online really is a lot of fun, but I think that's just the role-player in me who loves levelling. I managed to get to level 4 without any effort at all, but like most online games, it's very easy to be swamped by those more skilled than you - especially when you're a lowly noob.
For COD6 (let's pretend the non-IW COD5 set in WW2 doesn't exist):
- Let me knock out the lights, and make the AI respond appropriately
- The themed levels - night time stealth, lone sniper, the rescue your friends - are pure gold, and really help compartmentalise a varied experience
- Great weapon selection, with the auto-shotgun being a personal fave. Try a little more variety for the rifle-type weapons, since the default marine weapon being easily the most comfortable.
- I know it's a COD staple, but infinite respawning AI is a terrible mechanic. Let me clear a path and move on if that's how I like to play.
- Try Halo-style online matchmaking. Dropping a level 1 into a server with four or five people going for their final prestige run is a bad thing. Skill-based matching is an obvious mechanic - make it happen.
Overall, I was pretty down on COD4 before I got a chance to play it. Lucky for me I managed to win a copy, and I had a
lot more fun than I expected. I don't think it was GOTY, but it would be on my top five or so.