Authoring tools and a player software package that will allow for the creation and play of custom Left 4 Dead 2 campaigns for the PC were released Wednesday by Valve.

Players wanting to play home-grown campaigns will need to install a sizable update (available via Steam under the Tools heading) in order to play new, user-made content. The good news is that once you’ve updated, you can start playing right away — this new update works on mods for the original Left 4 Dead.

Valve’s campaign-creation tools add new tweaks like the ability to leverage the A.I. director’s “angriness” and make changes to the game landscape, and will allow modders to create Scavenge games in their maps.

Image courtesy Valve

Yes, this is the South, so you’ll come across a John Deere or two in your journey from Savannah to New Orleans, whacking scores of infected with frying pans and axes. Left 4 Dead 2 looks to retain most of the gameplay established in the original, adding new infected like the Charger and four all new Survivors. Also new: fiddles.

The sequel also adds a little more clear military involvement, as you can see in this raw gameplay footage. Those air strikes were hinted at in the game’s original teaser trailer, but we get to see them in action here. Also previously seen, but briefly, is the new pipe bomb effect, which sends some infected flying, rather than turning them all into red mist.

Take a gander and see if there’s anything we failed to point out during our hands-on time with Left 4 Dead 2. Let’s hope the new footage is more warmly received than the idea of a sequel itself.

Left 4 Dead 2 is arriving almost a year to the day after the original of the first, partly because the team responsible went to work right away on the sequel, without taking the standard week off to recharge. Much of the core gameplay from Left 4 Dead will be intact in the sequel.

And at this point, when Valve still has yet to reveal—let alone tweak—the two remaining planned additions to the Special Infected. That’s on top of the already revealed Charger class, the half-Tank that addresses on of the problems with the original Left 4 Dead‘s game design.

Yes, there are problems. Characters stacking themselves upon each other during crescendo events, for example, backing into closets and behind gurneys and rendering zombie horde rushes moot.

The Charger will fix some of that, Valve’s Chet Faliszek says. Designed to break up tightly packed groups, then pounce upon one of the Survivors like a Hunter, the Charger is big and bulky, like a Tank, but doesn’t take nearly the amount the amount of gunfire to take down.

My handful of run ins with the Charger weren’t that dramatic. But the AI controlled Special Infected did take me down at least once, requiring my teammates to revive me. The Charger should be fun to play, as he’ll be added to the regular rotation in Left 4 Dead 2‘s Versus mode.

Faliszek wouldn’t say what the other two Special Infected types planned were, but teased that we’d get to hear more about one of them later this month, another later this year.

Also adding to the variety of Left 4 Dead 2 are the new melee weapons. Keep in mind it’s melee or main weapon; if you have a shotgun, then pick up an axe, say goodbye to that shotgun. Your arsenal hasn’t expanded beyond one main weapon and pistols. The melee weapons are definitely powerful though, so you’ll still be a deadly zombie slaying force when wielding a frying pan. Those close range attacks may become a beneficial addition to your Survivor squad, especially with the new, very noticeable change to regular infected.

They’re a little more challenging to kill. Shoot off an arm and they won’t just lie down. They’ll keep coming. Add to them the new regular Infected that wear haz-mat suits won’t burn when you set them alight with a Molotov cocktail and the rank and file zombie becomes a more serious challenge.

Also new are the extended crescendo events. In the demo we played, set in the level “The Parish,” that involved jumping out of a CEDA truck, then running a gauntlet of zombies while navigating a maze of chain link fences. The crescendo ended when we shut off a klaxon alarm at the top of some rickety looking scaffolding. It’s a tension filled new addition to the plant and shoot crescendo events from the first Left 4 Dead.

While not present in the demo we played, there are additions to the grenade class of weapons used in the game. It’s still strictly Molotov and pipe bomb for now, but Faliszek says those items will expand. The same for new ammo types. All that we played with were the new incendiary rounds—which thankfully set a Tank on fire with a little more reliability—but expect more.

Speaking of weapons, we played with all of them. The arsenal is similar in gun type to the original—sub machine gun, shotgun, semi-automatic rifle, sniper rifle, auto shotgun—but they feel different. I didn’t verify this with Valve, admittedly, but the Left 4 Dead 2 auto shotgun felt a little slower in its rate of fire than its Left 4 Dead equivalent.

Finally, the biggest change in L4D2 was its daytime setting. It made infected a hell of a lot easier to spot, especially those chunky Boomers. Perhaps too easy to spot. It’s not a change I’m all that excited about, really, because it takes away from some of the tension of the perennially dark original. But it will be, let’s say, interesting to see how it effects Versus mode.

In theory, there are a few more changes coming. Faliszek said Valve may be exploring “variations” to already established classes like the Hunter and Smoker, but expects they’ll retain their original visual design. And there may be other tweaks, including the option to double up on reviving incapacitated Survivors. All this is being playtested and iterated, but since Valve “adds very carefully,” these changes may not make it to the final version.

We’ll have more details from our Left 4 Dead 2 play session later. For now, enjoy some new screens.