I never played the previous Left4Dead so I can’t compare the two. I will try to share my (short) experience of the game, we could only play it for 10 minutes.

More funny than scary, at least for me, L4D2 is the latest Biohazard’s perfect challenger. It has way more weapons, is a lot of fun and has even funnier monsters like zombie clowns and jockeys…

L4D2 is even funnier in co-op mod, you can hunt Zombies with friends like my grandfather and I hunted ducks… You can even create your own rules by selecting one of your friends as bait to lure zombies… (Being the bait is pretty funny too)…

L4D2 is an excellent game, and since never played the previous version I don’t have any complaints for Valve.