What systems is it for and how much does it cost?
L4D2 is still exclusive to the Xbox 360 and PC, sorry Sony and Nintendo. The 360 version will run you about $55, the PC version $45.
Does it follow the Left 4 Dead storyline?
No, it doesn't. While it follows the same episodic format, L4D2 does have campaign-to-campaign continuity that tells the story of four survivors of the zombie pandemic as they try to fight their way from Savannah, Georgia to New Orleans, Louisiana.
Who has replaced Louis, Bill, Francis, and Zoey?
It's the same three guys, one girl dynamic, but this time around the survivor characters are Coach, Rochelle, Ellis, and Nick.
What about the special infected, anyone new there?
This is probably where the changes will be most notable. Not only are there three new special infected joining the Hunter, the Smoker, the Witch, the Tank, and Boomer, but there are also unique members of the horde as well. There are zombies who wear HAZMAT suits and are thus fire-proof, and there are also clown zombies whose squeaking shoes will alert more of the horde, plus a few other hidden treats.
As for the special infected, we've now got the Charger, who does exactly what his name implies, the Spitter, who does exactly what her name implies, and the Jocket, a creepy little guy that jumps on your head, steering you around until someone shoots it delicately off of your head.
Oh, and the Witches don't just sit in a corner crying any more, sometimes they wander around.
What's new item wise?
There are a handful of new guns in both the small (ie pistols) and big (ie grenade launcher) variety, but the most noticeable is the inclusion of melee weapons. So if you felt the only problem with L4D was a lack of fire axes and chainsaws, you're in luck. (There's also a baseball bat if you pre-ordered from Gamestop like I nerdily did! --sw)
There are also an array of new support items as well, including an adrenaline needle that allows you to run faster, a defibrillator that can bring dead teammates back to life, and a grenade made from the bile of a Boomer, which can cause the horde to attack whatever it's thrown on.
What's new gameplay wise?
In addition to five all new campaigns at launch, the game's A.I. Director will now give you tasks to do during certain portions of a campaign (such as find 13 gas canisters to fuel up a car) and also has the ability to alter wall placement, which should liven up repeat play-throughs of the same levels. You can also expect a new array of visual tweaks, like thick smoke and rain, that make it harder to see the horde around you. The better you are, the harder it rains.
There are also two new modes joining Campaign, Versus, and Survival: Scavenge and Realism. Scavenge mode gives you an objective, such as keeping generators fueled, and will rank your score depending on how well you perform the task. Realism mode is a new tweak on Campaign mode, which removes your ability to see player's outlines through walls, puts the emphasis back on head shots, and makes it so that players can only be brought back to life with the defibrillator.
But is it any good?
Of course, it's good! All horror sequels are good, right? Kidding aside, I've only played it for a few hours but all of the tweaks have definitely given new life to a game you most likely stopped playing months ago. Some of the additions, like the melee weapons, are kind of pointless and the characters aren't as memorable, but the revamped A.I. Director combined with new baddies makes up for it. Basically, if you had a blast playing the first L4D with your friends, L4D2 is going to be just as fun. If you grew tired of the first game after a few weeks with it, this isn't, unfortunately, revolutionary enough to keep you on for any time longer than that.