IGN writes:
"Believe us, we could write all day about Left 4 Dead and Left 4 Dead 2, and we have. Whether it was our huge E3 preview of L4D2 or our recent look at some of the new user-made maps for L4D. Valve's zombie franchise is a lot of fun to play.
But we're also aware that there's a lot of curiousity about Left 4 Dead 2 because much about the game has yet to be revealed. So we've condensed down a quick comparison chart to highlight the differences in the two games."