Killing Floor 2 exclusive first look: co-op FPS horror with the most advanced gore system ever

Wes Fenlon


Paris is burning. The sky behind the Eiffel Tower glows an ominous orange through a haze of billowing smoke. Sparks and ash and scraps of paper float through the dark streets of the city, where cars and offices stand eerily abandoned.

A manhole opens. For a moment, nothing happens. And then a zed, a naked genetic freak sheathed in slimy grey skin, pops out of the hole like a horrorshow jack-in-the-box. The zed has the mind of a child. It doesn't know much, but it knows it wants to kill.

The zed manages two steps from the manhole before a stream of bullets blast it off its feet. More bullets tear into it in midair, splattering blood across the street and unburdening its gut of a generous helping of internal organs. Everyone in the dark conference room at Tripwire Interactive laughs or oohs as they watch the most complicated gore system in gaming—a gore system they've been building for Killing Floor 2 for the past two years—eviscerate the zed in a way they've never quite seen before.

Since shipping World War II FPS Red Orchestra 2 in 2011, Tripwire has dedicated itself to the sticky art of digital dismemberment for the sequel to 2009's co-op wave-based shooter. They want each and every exploded brain, severed leg and bloody gutshot to look unique. Bill Munk, creative director and senior animator at Tripwire, has a saying: Red Orchestra is realism. Killing Floor is coolism.

"Killing Floor is a simple game," says Munk. "You have weapons. You see something that looks messed up. And you kill it. You get money for doing it and you buy better weapons. Rinse and repeat. The more enjoyable that small little loop is, the more successful the game is."

Munk is one of Tripwire's co-founders. He couldn't hide his enthusiasm for games if he tried; over dinner, he gushes about how he played a borrowed copy of Metal Gear Solid in his college dorm for an entire weekend, substituting caffeine for sleep. When Munk talks about Killing Floor 2, most of his sentences end with "as sick as possible."

"This project on an animation end has been a dream come true for me," he says. “This is the first time we had the budget for me to do mocap for everything and try to make everything look as sick as possible."

When Munk says everything, he means it. The gun animations are mocapped. Melee is mocapped for first- and third-person perspectives. Killing Floor 2 is still a simple game. But this time, it looks good .

A killer mod

"[Killing Floor 2] is the first time we've been able to develop a game from start to finish with what I would call a reasonable size staff and a reasonable size budget," says John Gibson, Tripwire's president and a co-founder along with Munk.

Gibson is entertaining and outspoken for a company president. Tripwire's pedigree for realistic weaponry stems from Gibson's passion for them. Many guns in Killing Floor 2, like the Commando class's SCAR Mk 17 and AK-12, are modeled from his own personal collection. If he's not talking about guns or videogames, there's a good chance he's talking about cars. "Have you ever ridden in a DeLorean?" he asks me with a grin when we take a break for lunch. I have now ridden in a DeLorean.

Gibson and the other founding members of Tripwire had to take out loans to pay for their first game, Red Orchestra. They started as an Unreal Tournament 2004 mod team. Killing Floor was another Unreal mod, created by Alex Quick. Once Tripwire turned RO into a standalone game, they convinced Quick to port over Killing Floor. They played the mod so much, Gibson put Red Orchestra 2 on hold mid-development to turn Killing Floor into a full game. Ten people made the game in three months. As of 2014, Killing Floor has sold nearly 2.5 million copies.

Tripwire is now 50 employees strong. Killing Floor 2 is coming to Steam Early Access for Windows and Valve's SteamOS. When? Not as soon as I may want, Gibson says, but sooner than I may expect. After watching them play KF2, I know they got at least the first half of that statement right.

MEAT and bones

Bullets, blades, and blood: these are the pillars of KF2. They're represented by a diagram like the classic food pyramid, except each ingredient gets an equal share. The pyramid sprouts guns and blades and is coated in blood like a heavy metal porcupine.

"When we started designing the game we decided gore was going to be the most important feature," says David Hensley, art director on Killing Floor 2. "We were really inspired by Soldier of Fortune, the GHOUL system. We wanted to outdo Soldier of Fortune's gore."

Hensley has been with Tripwire since the beginning. He and Munk went to college together. When they moved to Atlanta, they slept on air mattresses in an apartment shared with other members of the studio. He couldn't afford a car until they shipped Red Orchestra.

Hensley uses a pistol to slowly tear apart Cysts. The Cysts are new, weaker Clot variants—the underdeveloped killer babies of the genetic freak family. Each zed in KF2 features 19 points of dismemberment. "You can blow chunks off their head to reveal skull," he says. "Keep shooting the skull and it explodes, revealing brain cross sections. You can cut them in half vertically, horizontally."

Tripwire calls KF2's gore system MEAT. Massive Evisceration and Trauma. It's more detailed and graphic than Soldier of Fortune's GHOUL system, but it's not as disturbing as seeing realistic human faces blown apart. Killing Floor 2's zeds are genetic freaks pulled from the workshops of schlocky sci-fi horror films; their gruesome dismemberments are designed to elicit cheers rather than grimaces. And it works—every katana appendectomy and mid-air slow-mo headshot puts a grin on my face. These bodies have weight when they fall apart, and they get torn up in all kinds of nasty ways. But Killing Floor 2 is colorful and exaggerated enough to teeter back from the edge of disturbingly realistic violence.

Still, there's enough blood in KF2 to make Sam Raimi envious. And here's the crazy part: it stays. Bloodstains become permanent fixtures of Killing Floor 2 maps for entire matches. Tripwire's designers grin mischievously when I ask how they did it.

"We're using some really clever tricks to modify textures in the level in real time," says Gibson. "Typically blood is rendered as a texture that is projected onto objects in the world. It's very expensive to render. What this is doing, in real-time, is modifying the textures being rendered to display the blood so there's almost no additional rendering cost. You can literally paint the texture with blood and it'll stay the entire match."

For added variety, each zed has 95 death animations divided between kill zones—the head, neck, chest, stomach, and limbs. Thanks to Killing Floor's success, Tripwire had the money to hire a mocap expert and record every zed movement at a motion capture studio in Los Angeles. Munk captured 3000 motion capture clips for the zeds, and melee attacks, and gun reloads. The once-stolid zeds that clunked around like Unreal Tournament bots are now alive, swaying and howling, lunging and beating their chests. Gollum's Andy Serkis would be proud.

Tripwire's guns, already renowned for their realism, also benefit from Killing Floor 2's focus on animation fidelity. "Guns shoot at such a high framerate, if you animate the gun at 30 frames per second, you're only going to get six frames per second when you go into slow-mo to show that gun animating," says Munk. "We started experimenting. What happens if we animate our weapons shooting at ridiculously high framerates? Using the Bullpup as an example, we animated at 242 frames per second, which gives us 22 frames per shell that ejects out of the weapons. In slow-mo you can actually see every kickback."

Blood on the streets

Hensley opens up a co-op game lobby—an addition to KF1's classic server browser—which is quickly filled by five Tripwire testers elsewhere in the office. Most of them play with level 25 perks, KF2's new level cap. Two skills unlock every five levels, but only one can be equipped from each pair. There's always a tradeoff. The Commando has to choose between a damage boost and a skill that shows his entire team the zeds' health bars.

The new perk abilities add variety and, more importantly, a longer level curve for players to work on. In KF1, players could go months without earning a rank up, and each perk had only six ranks. "A big goal for us this time around is to make sure the endgame, playing the game for a long time, is much more entertaining and has a lot more replay value," Gibson says.

Hensley starts the match on Hell on Earth, the hardest of four difficulty settings. Tripwire removed one difficulty option from the first game and completely redesigned how difficulty scaling works. In KF1, zeds simply moved faster and soaked up damage like lead-starved bullet sponges. In KF2, zeds become more aggressive and gain new abilities. Clots that would stumble around in a daze on normal charge towards Hensley in a fury when he shoots them on Hell on Earth. Spider-like Crawlers pour out of vents in the walls and ceiling and scurry around in the darkness.

Larger zeds, like the bile puking Bloat and the hulking, spike-handed Fleshpound, can already eat magazines of ammo on normal. I don't see them unleash their full moveset on Hell on Earth, but I expect they'll be more threatening, and more fun to fight, than they are in KF1.

Hensley's team move through the streets of Paris, first killing zeds with pistols, then upgrading to more powerful rifles and shotguns. Each perk has four primary weapons. That's 40 weapons across 10 planned perks, but Tripwire says there will be others—backup melee weapons and "sidegrades" that won't ruin game balance.

The Tripwire players move from the streets of Paris into an abandoned hotel, then out into a dimly lit courtyard and underground into the subway. Hensley pulls out a katana to protect teammates as they reload. Melee has been completely reworked for KF2, with light and heavy attacks, combos, and four-way directional swings. A narrow hallway in the subway becomes clogged with bodies as Clots pour in and fall to concentrated gunfire. When Hensley swings his flashlight over the walls, they're coated with blood.

The team lasts three waves. Without welding doors shut to protect their backs, hordes of zeds overwhelm them. Paris burns on, overrun.

Destructible dynamic lighting and vents and manholes that spawn zeds encourage movement around KF2's varied maps.

Modders at heart

Killing Floor 2 is still Tripwire's baby. They're raising it, molding it in their image. But eventually, it will become the community's game. "Every system that we make we're looking at how to make it extensible to modders," Hensley says. "We'll design a system and then go 'oh, that's not going to work for modding. So we'll redesign it to make it easier for modders to access."

KF2 will support Steam Workshop for mods. Tripwire will release a mod SDK. "That's one of the things we're very adamant about," Gibson says. "We like to prod DICE and EA on this one occasionally. They've essentially come out and said that games have progressed to the point [that they] don't believe the community can make content for [their] games. I say that's total BS. People are smart. That's selling them short. They will figure out their tools. If we can do it, smart kids out there are going to figure it out too."

The gore and animation systems will be extremely open to modders. Limbs and damage types can easily be assigned different effects. Zeds could spew flowers and rainbows instead of blood. Modders will be able to assign zeds new attacks without writing any code. Even Tripwire's lighting system, which is they built themselves and integrated into Unreal Engine 3, will be easy to animate.

The fans still playing Killing Floor years after its release made Killing Floor 2 possible. Those are the people Tripwire wants to reach through Early Access, to get their feedback on weapon and perk balance. Bill Munk, most of all, seems like he can't wait to get Killing Floor 2 into the hands of fans. At the same time, he's putting everything he's got into it.

"When we first started, we didn't have two pennies we could scrape together, but we've always been really ambitious," Munk says. "It's our goal to have one of the coolest video game companies in the world, an oasis, a place kind of like Valve, where we make stuff that would never exist if we didn't exist. But we've had to bleed to get to that. ... Now I feel like, for me, this moment is what I've worked towards for 10 years since we first started. We have a full crew of elite professionals, we all know each other really good. We all know how to use the engine. We all believe in this game. I'll do whatever it takes to make this product as sick as possible."

This reveal of Killing Floor 2 is the first part of our coverage of Tripwire's new co-op shooter. Subscribers to the US version of the magazine will receive an exclusive PC Gamer character skin in Issue #254 . Come back tomorrow for an in-depth look at Tripwire's approach to weapon design and an interview with president John Gibson.

About the Author
Wes Fenlon

As hardware editor, Wes spends slightly more time building computers than he does breaking them. Deep in his heart he believes he loves Star Wars even more than Samuel Roberts and Chris Thursten, but is too scared to tell them.

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