UPS dood brought my Left 4 Dead at 3pm today. I played through the first campaign, and wow. I couldn't stop until the campaign finale.

There are 4 campaigns, composed of 5 chapters, with the last chapter being a dig-in and wait for rescue climax. According to the campaign stats, which scroll up the screen at the end of the campaign like movie credits, it took me 2 hours 51 minutes. I died once in the sewers and had to restart that chapter from the safe room at the beginning. At the end, we held out long enough for the helicopter to arrive. I was playing with 3 AI controlled characters; none of my friends have it yet, hint hint. Bill and I got onto the helicopter. I look back and Zoey is on her way, but Louis is being shredded by a Hunter. I hopped out thinking I could save him, only to be knocked off the landing platform and swarmed over by the horde. The other two died as well. The helicopter took off with Bill, the one remaining survivor. Even though I died, I got the achievement for the campaign, apparently since SOMEBODY survived. All told, I earned 10 of the game's 50 achievements, for 160 points. We killled over 3,500 zombies; I killed just under 1,100 of those. My accuracy was 35% ... a lot of spraying a machine gun or assault rifle. Also the stats told me that the AI characters never threw a Molotov or pipe bomb.... which may be OK because in close quarters that's not wise... I caught on fire a few times because of the spreading fire or because the Horde pushed me into the fire.

The game is drop-in-drop-out in both campaign and versus modes. I haven't tried versus yet, but in case you didn't know, you can play as one of the infected bosses too. When you hit the start button, the game does not pause. This of course makes sense in multiplayer mode, but even by myself the game kept going. If there is another human playing, the "Take A Break" option on the menu appears, and choosing this lets the AI take over for your character until you get back, allowing everyone else to keep going. I took breaks inbetween the chapters while inside the safe rooms that bookend the chapters. If you stand still too long, the AI will throw hordes at you... a quick way to get seriously hurt and deplete your ammo.

So, doing the math, if you were to play this once through in campaign mode, it might take 12 hours (almost 3 hours for my campaign #1 times 4 campaigns). There are four difficulty levels, and I played on "Normal", the second hardest. Hopefully the versus mode will be worth some significant time as well; we'll see. Playing as the infected will mix it up a bit.

P.S. I left Faith partway through Chapter 4 (of 8 apparently) in Mirror's Edge... these two games are clearly like night and day, although both have "180 degree spin" mapped to the right bumper... so Faith can launch off walls and so the survivors can better fend off the horde in chokepoints....