Players will still find simple additions, but that's not the meat (and brains) of what's new.

Make no mistake, Left 4 Dead 2 is the same game that players fell love with last year. The mechanics are exactly the same. As explained to me by Valve's Chet Faliszek, the goal in creating the sequel wasn't to make the game more complicated, but to refine the experience of the original and make it better. Players will still find simple, bullet point additions like melee weapons, incendiary ammo and new special Infected creatures to rain on the zombie killing parade -- like the crowd-breaking Charger -- but that's not the meat (and brains) of what's new.

It's fun to hack away at zombies with a fire axe (there's a frying pan too, by the way), though it requires sacrificing long range attacks. Incendiary ammo turns every shot into a one-hit kill, but it only lasts for a single clip, meaning players have to be more careful with their shots (don't waste them on the zombies in Hazmat suits, they're fireproof).

There will be five campaigns, all of which will be playable in every mode -- campaign, versus, survival and a fourth secret mode -- from day one. All of these additions are immediately noticeable, but some of the most exciting changes are things that aren't quite as tangible.

Faliszek noted that Left 4 Dead followed a very rigid formula: Fight through several sections, run from safe room to safe room and finally survive a giant wave of Infected as they flood a defensible location while the Survivors wait for rescue (the "crescendo moment"). This formula led to players yelling at each other for not playing the game "right" if they didn't stick to a rigid strategy that might not necessarily be entertaining. The solution, according to Faliszek, was to create crescendo moments in which the most fun way to play was also the best way.


Enter the first crescendo moment of "The Parish" in Left 4 Dead 2. The Survivors enter a courtyard of twisting alleyways of chain-link fence, with a tower in the center. An alarm sounds as the Survivors enter the courtyard, bringing the horde with it. The only problem (um, besides armageddon)? The switch to shut off the alarm is on top of a tower in the center of the courtyard. Thus, instead of defending a static location until rescue arrives, the Survivors have to battle through a gauntlet of Infected and make their way to the tower where they can shut off the alarm and stem the tide of living dead.

Valve will be creating many different kinds of crescendo moments for the game that change the play in different ways. For example, Faliszek mentioned that one takes place in a car impound lot. The catch: Every single car has an alarm. Faliszek said that Valve has actually managed to make it through without setting any off, but we get the feeling that won't happen very often.

It's much more than a simple expansion of the original.

Significant improvements have been made to level design, utilizing the expertise of Portal designer Kim Swift. Some levels will have sections that have changing layouts. Faliszek mentioned a graveyard that would be different for every playthrough, for example. The AI Director can make the path through the graveyard longer or shorter depending on how well the Survivors are doing. Another level begins in total daylight, but darkens as a storm rolls in. The storm reduces visibility to nearly nothing, making it hard to spot zombies and, worse, teammates (their outlines won't appear in the fog). Faliszek compared it to the cornfield in L4D's "Blood Harvest."

With so many changes to the gameplay systems in Left 4 Dead 2, it's clear that it's much more than a simple expansion to the original. And yet, it is still the same game on the surface. Whether or not the most significant changes will manage to dull the sting of forking out the cash for a new retail game, we'll have to wait and see. Either way, one thing is clear -- it's still damned fun.