A game that no FPS fan should miss for any reason.
I'm not sure there was ever a FPS that was quite as ambitious as this in so many ways.
The models and skins are dark and creepy, the setting is just right for a zombie survival fan such as me, and the _feel_ of the game is perfect.
I played the demo of this a couple days before it came out, and spent (without boredom or regret) literally hours on the very meager amount of game that was allowed. Once it came out I bought it and played non-stop (or so it felt like) for days.
The game is divided into four major campaigns, all of which are very unique in design, challenge and setting. All of which are centered around the survival of the four main characters. There are no RPG elements to the game - no customization of characters, no difference in ability or play style of the different characters - but it also doesn't feel like something is missing from the game. That's because of the gameplay itself
The gameplay is some of the quickest and most intense I have ever experienced. Between the mild packs of semi-docile zombies sitting around come randomized attacks by the "special" zombies of the game, as well as massive hordes of running, screaming zombies. The implications of these things are intensified to the extreme in Expert mode, in which everythings' damage is what I'd call "realistic".
The "drop in drop out" style of multiplayer is also nice. Whenever there is less than four humans in a game, bots will automatically assume control of the missing character. They are not amazingly programmed, but I would put their AI system as being higher than most bots in shooters. At least they're never guilty of friendly fire. :)
Some might complain about the selection of guns, which is meager, but it also didn't feel incomplete. The guns themselves had a good, real feeling to them (despite the hyper-accuracy of the pistols), and all serve their own, unique purposes.
For those who enjoy good old head to head competition with others, there is also an extensive multiplayer within the game, in which the players take turns playing through the normal campaign levels, and the zombies trying to harass them as much as possible, hopefully killing them.
Probably the only real downside to the game is the play time factor. It really doesn't take all that long to play through the campaigns, unless you're forcing yourself to only beat them on expert. Even then, 2-3 solid days of playing will easily allow you to see everything this game has to offer. Personally, it has a great deal of replay value, though if someone doesn't glean a lot of value from playing through something again, then I could understand a degree of disappointment with the game.
Overall, I think this game was presented flawlessly. It's creepy as hell, fast paced, and with real feeling guns and action. Expert mode is no joke, even for good players, and the campaigns really stress your abilities and concentration. It also runs brilliantly at max settings, especially considering how freaking much is going on at times. From big open spaces, to super enclosed levels, I never really experience any kind of video stutter, and that's with less than top of the line equipment.