Nevermind the Bollocks, here's the Zombies!
That's what they should have called this game. No long winded story about vials in labs or infected monkeys, just "You are here, you need to get there, there are zombies in the middle, go."
In short this is the perfect Zombie game, just because there is so little to it, just like the best zombie films (ie, pre-1990's). Not since the original Doom has any game managed to nail this simple idea and still be able to keep the levels fresh and exiting. By all rights Valve could have had this long drawn out viral marketing campaign with the back story in the form of comic books or some other kind of crappy merchandise. But I think that they realised the one thing that has become apparent to me after playing this game for so long; the story of the four survivors, as endearing as they become, is never the major factor in this game, it's the story of the 4 people playing the game that is always the most interesting.
This game is full of those " Do you remember that time when we........" moments. Also it has to be said, I never play this game single player, always with my Wife and two friends, and I think that's what makes this game such a hard thing to review, for the experience you have will be totally defined by the people you play it with, not the game itself. Play it with people you like and love, and you will have a bonding experience like no other, phrases like "please help me", "Hey stop shooting me" , "I didn't shoot you what are you talking about ", and my favorite "Shut the F****** Door!!!!!" all are met with jovial laughter and tit-for-tat comments. Play it with strangers, or with the younger generation on XBL and suddently these same phrases are usually met with distain and hostility.
Lastly Valve have build on their experience making Counterstrike and Team Fortress 2 and made a game where teamwork is everything. If you admire John Rambo as a role model, this game is not for you. That's not to say this game is full of Red-Cross workers by any means. But in no other game thus far has it ever dawned on me that my most valuble asset as a means to getting to the end of the level are my teammates.
To conclude, a long time ago, I got a 14.4 modem for my 486, and played Co-op Doom and Doom2. It was awsome. This is the game I have been waiting for since then, and you know what, it's still awesome.