Yah, I've played the demo. It's pretty friggin' fun too, yet completely different. Besides, are you in the World War II era using World War II guns and fighting Nazi zombies? No, your stuck with an old guy, a black dude, a girl, and one cool guy, doing the typical zombie stuff. Not saying it's bad or anything, it's just that you shouldn't compare the two yet since Left 4 Dead isn't even out yet and that you haven't played CoD's zombie mode (or from what I'm guessing?).