Killing Floor Prototype: the UT2004 Mod Builds
Before Tripwire Interactive turned it into a retail game, Killing Floor was a total conversion mod for Unreal Tournament 2004. It was made by Shatterline Productions: Alex Quick, Mark "Marco" Welch, the composer zYnthetic and a handful of other contributors. The mod had four public releases (KF Mod 1.0, 2.0, 2.1 and 2.5) and a fifth, 2.51, that never shipped officially because Tripwire hired the team to rebuild the game on the Red Orchestra branch of the engine. The 2.51 files still circulate among people who worked on it.
This page collects what the mod builds show: content that survived into retail in a very different form, and content that was dropped along the way. Some of the material comes from the August 2026 Steam2 Content Server Dump.
Note: this page contains NSFW material (nude zombie women).
Known builds
- KF Mod 1.0 demo (April 8, 2005): a cut-down demo built from an early version of the mod.
- Pre-release build (May 12, 2009): a Killing Floor build compiled two days before the retail launch.
An unused Siren face effect texture associated with the May 12, 2009 build.
Differences from retail
Content that made it from the mod into the retail game but changed a lot on the way.
Characters
A few characters moved from the mod to retail, but most of them kept little more than their names: their looks changed completely.
Lt. Masterson
In the mod Masterson is a sergeant. He appears in the 1.0 single-player campaign, but not as a playable character, so he has no portrait or description.
Masterson in KF Mod 1.0.
When 2.0 and 2.1 dropped the single-player mode, he went unused.
Release 2.5 added a different clone of him as a playable character, with the model and textures redone in the mod's new visual style.
Masterson in 2.5.
His 2.5 portrait.
Description: When a DRF specialist infiltrated the Horzine biotics laboratory and killed the Masterson clone, that was the last anyone thought they would see of the man. Ironically , it was weeks later that another team found a working incubator in the derelict lab with his genetic footprint. The result was a fully functional clone, who now aids the DRF in putting down the remaining failed specimens.Police Sgt. Davin
In the mod Davin is a private in the DRF (Disaster Response Force). He arrived in release 2.0.
Pvt. Davin in 2.0.
The 2.0 portrait looks like it was made from an earlier model: the hair and beard differ.
Description: Private Davin is a new recruit in the Disaster Response force. He grew up in a poor Irish community and learned some of lifes lessons the hard way. Despite his rank, he is one of the more reserved, and mature members in his squad.In 2.5 his portrait was redrawn in the new style.
Davin's 2.5 portrait.
KF Mod 2.5 character descriptions
The mod's character descriptions as translated on the killingfloor.ru forum ("Описание персонажей из KFmod2.5" thread):
- Hazmat - a former Horzine employee, a secretive man behind the research and development at the Horzine Biotech Laboratory.
- Soldier - just a soldier.
- Black soldier - a commander of the rapid response force. When the outbreak of test subjects swept London, these soldiers were the first on the streets to protect the population.
- Davin - a private, a rapid response force recruit. He grew up in a poor Irish community; despite his rank he is one of the careful and seasoned members of his team.
- Kara - Sergeant Kara Burns from Liverpool, a marksmanship expert by 18; she joined the rapid response force after being expelled from school.
- Lewis - bald, fat and angry.
- Masterson - when a rapid response force specialist killed the Masterson clone in the Horzine biolabs, he thought he was the last to see him. Weeks later another team found a working incubator with genetic remains in an abandoned lab, and it produced a fully functional clone who now helps the rapid response force wipe out the remaining test subjects.
- Powers - a corporal with a reputation as a nasty bastard.
- Urban - a rapid response force soldier in urban camouflage.
- Stalker - Claire, whom the rapid response force captured and taught table manners, toilet use and firearms so she would help hunt down her former "colleagues".
Removed content
Content that existed in the mod and was removed for retail, or removed from both. Some of these assets still sit in the retail files. Later mod versions sometimes contain updated versions of the same assets.
Assets
"GK" packages
GK packages have shipped unused since the first release of KF Mod 2. They do not look like Killing Floor content at all and probably belong to some other project; what it was, and whether it was ever made, is unknown. GKStatics is a static mesh package with a few basic shapes and pinball parts, none of which have textures assigned.
Pinball ball.
Button.
Pinball paddle.
Ball pusher.
Round bouncer.
Triangle bouncer.
Beveled brick.
Domino.
The GKTextures package is more interesting: it holds actor sprites, a set called "DemoLevelObjects", a cubemap and a few flat colors (black, red, blue and two grays).
The actor sprites.
"DemoLevelObjects".
The cubemap.
KFExplodingBarrelDeco
The mod had explosive barrels that stopped being used after 1.0. Their texture was still updated in 2.0 and later, and became much brighter.
The 1.0 texture.
The 2.0+ texture.
KFGrass
A static mesh package with modified Unreal Tournament 2004 assets. It was removed from the files for retail.
Grass.
Gnarled tree.
Barbed wire.
Shrub.
Characters
DRF Commando
KF Mod 1.0 introduced generic soldier characters with no personality of their own, and they did not make it into the retail game. There were three versions, Normal, Black and Urban, all on one model with different textures. They share a portrait and description, and all three are simply called "Soldier".
Soldier.
Soldier_Black.
Soldier_Urban.
The portrait shared by all three.
Description (All): DRF commando. When the outbreak struck London, these courageous soldiers were among the first to hit the streets in defense of the public.Release 2.0 updated the model. Soldier_Black and Soldier_Urban lost their textures but could still be selected. The normal Soldier got new textures borrowed from Davin; the descriptions and portraits stayed the same. The models also gained extra geometry and a material slot for a scripted texture called NameTag. It was probably meant to show the character's name on the uniform, but in game it is broken and shows the gas mask texture instead.
Soldier in 2.0.
Patch 2.1 fixed Soldier_Black by giving it Powers' texture. Urban stayed unfinished.
Soldier_Black in 2.1. The 2.1 textures are oddly blurry for unknown reasons.
In 2.5 Soldier_Urban finally got textures, and all three got a new portrait. The broken NameTag texture became a static name tag reading PVT. Jim. The regular Soldier's description was removed entirely, and Soldier_Urban got a new one. A different package from the other characters also contains an unused duplicate of the body texture, an unused gas mask variant and an unused Soldier_Urban portrait.
Soldier_Urban.
The updated portrait for all of them.
The unused camo gas mask.
The unused Soldier_Urban portrait.
Description (Urban): DRF Soldier in Urban camoNothing changed for them in 2.51, but a fourth variant with its own model was added to the files. It is only labeled Horzine, so it would presumably have been called Soldier_Horzine. Only the model exists, with no portrait or description.
The Horzine soldier.
Sergeant Kara Barnes
Kara is a character cut from the retail game who exists in the mod. She was added in release 2.0.
Sgt. Kara Barnes, although her name tag says Lt.
The portrait seems to be based on an earlier version of her model: the hair is different.
Description: Liverpool born, Sgt. Kara Barnes was an expert marksman by the age of 18. She joined up with the DRF after flunking out of School.'When this is all over im gonna settle down. Have a family. And then burn the fucking house down.In 2.5 her hair texture was redone and looks much better, and the portrait was updated to match.
The updated hair textures.
The updated portrait.
She did not change in 2.51.
Private Quick
Alex Quick himself was playable, but only in releases 2.0 and 2.1. Why he was removed afterwards is unknown.
Pvt. Quick.
His portrait.
Description: Canadian Born, Private Quick was one of the few foreign applicants to make it into the DRF on the first try. Despite being almost perpetually intoxicated, his aim never seems to suffer.Hazmat
Release 2.5 added a character simply called Hazmat.
Hazmat.
His portrait.
Description: Former Horzine employee. These shadowy men were behind research and development at the Horzine Biotics laboratory.Claire the Stalker
Release 2.5 also added a playable Stalker.
Description: Meet Claire. A DRF squad captured her, and trained her in table etiquette, the use of toilets, and finally, how to hold a firearm. All in the hopes that she put her rotting self to good use, and help tag some of her former 'colleagues'. So far, it's been a resounding success. She plans to join a book club when this is all over. And try on clothes.Maps
The mod shipped several maps that are absent from retail. TCRF lists them but has not documented them in detail yet:
- Story maps:
KFS-01.ut2,KFS-02.ut2,KFS-03.ut2,KFS-04.ut2,KFS-05.ut2,KFS-Intro.ut2,KFS-Outro.ut2,KFS-RESUMEGAME.ut2 KFS-Training.ut2KF-Sewers.ut2KF-Intro.ut2NvidiaLogo.ut2
Weapons
Two mod weapons did not reach retail: Claws/Fists and Bat/Broken Pipe. Their leftovers in the retail files are covered on the unused weapons page.
Enemies
The mod also had enemy classes that retail dropped: KFEnemySoldier, KFHumanPawnEnemy, ZombieWretch, ZombieSoldier, ZombieShade and ZombieGoreFastSP. Some of them still exist in the retail files, see cut content.
Related pages
Source
Based on Proto:Killing Floor on The Cutting Room Floor, licensed under CC BY 3.0.
