I was one of the chosen few who preordered the game and got to play this wonderful game.
Here are some quick thoughts.

- I like the new survivors. At first I was worried that the attention of detail given to the original four would not have been given here, but thankfully I am dead wrong. Each character has their little quirks and such personality that it's hard not to like them. For example, Coach (the big guy) will read just about every sign he sees. Ellis is the new Francis, except he is kinda like nega-Francis (He likes stuff). Nick is the sarcastic bastard, which in itself isn't that original a concept, but he plays the part so fucking well. Rochelle isn't as dorky (and awesome) as Zoey, but she is probably just as lovable in her own fashion (she is wearing a depeche mode shirt).

- The weapons are considerably beefier, not just in function, but in feel. Every gun feels stronger, and in a lot of cases the guns are stronger.

- All of the weapons from L4D1 are back, alongside their newer counterparts. You can go from using the new metal shotgun, back to the old Remington one. Better yet, each have their own attributes. For example, the new shotgun has a tighter spread and is better for range, but the old one does so much more damage on bigger targets (like chargers). The Hunting rifle from l4d1 can now be used while moving go great effect. In l4d1 you could barely crotchwalk with it and expect any semblance of accuracy.

- Having stronger weapons doesn't necessarily make the game easier, because the infected are stronger. The uncommon commons such as the riot gear infected actually require special attention and in some cases a team effort to dispose of. You seriously cannot just shoot them to death, you have to flank them or spin them around somehow. It's fucking hilarious seeing all 4 teammates trying to get the fucker to turn around so you can end it, while his body flails against whatever wall he's getting slammed against, repeatedly.

- The new special infected make playing this a totally new experience. You can't corner camp through an expert campaign anymore. The spitter can down someone that doesn't move in moments (even on normal), but as long as you make an effort to move, it's not hard to take 0 damage. This is great. Leading into this topic...

- There is a melee timer on campaign now. No corner camping.

- Melee weapons feel so good. I'm not sure how practical they are though. I know that using the new adrenaline and then using a melee weapon is fucking awesome though.

- New Items: Adrenaline Shot (Speed boost, zombie attacks won't stun you) Defibrillator (revives dead players, yeah I'm serious), Boomer Bile (works similar to pipe bomb, as it will attract zombies where it's thrown, except, you can throw it on zombies causing whatever it's thrown on to get swarmed. Have fun using it on a witch.)

[link]

Yeah, holy shit.