Typical gameplay consists of a single game type, single- or multi-player, in which the player fights waves of zombie-like specimens, with each wave becoming successively more difficult, moving through each area of the level, until it concludes with a battle with a "boss" specimens, called the Patriarch.[5] Alex Quick, the level designer and texture artist, stated that "there are a whole bunch of ideas on the drawing board that we can add in after launch, including the 'Story' mode from the mod, for instance."[6] A wave is completed when all the specimens are dead. Players can choose where to run and fight. Up to six players can team up in an online cooperative battle with the specimens. The game sessions are fully-configurable, so players can change the difficulty, number of enemy waves, or specify which creatures compose the waves, although certain combinations do not allow perk advancement. As the player progress through waves, the tougher-grade specimens are more commonly encountered. A software development kit (SDK) and level editor are included to aid in the creation of modifications and levels. There are a wide array of weapons, including melee weapons, shotguns, rifles, sidearms and other weapons. Players may accumulate money through killing specimens, surviving waves, from other players, and selling acquired weapons. This money can then be used for weapons, supplies, and ammunition at "the Trader" on completion of a wave. Where there is more than one trader point on a map, the trader location is randomised, as a mechanism to encourage players to explore the map. Current trader location is indicated to players at all times by way of a red arrow. A feature called "zed time" allows the player to see particularly gory kills, such as headshots, in slow-motion, even in multiplayer mode. It can also give the players an advantage for a brief time to carefully aim their shots. Tactical gameplay elements exist, such as the ability to weld doors shut to direct the flow of the enemy hordes, and the gameplay encourages teamwork by giving less of an energy penalty when players heal each other, instead of themselves. There is voice chat, and automatic, randomized voice responses from character interaction and selectable voice commands, for communicating with other players. Randomized music plays during set up and combat stages in each level. In set up, the music is generally ambient and quiet. In combat, it is louder, faster-paced heavy metal. There is a "Perks" system, which gives the player certain strengths and/or abilities. Players have seven to choose from. These are leveled up as their requirements are met, improving their effectiveness. For example, the Commando perk gives the player a discount on automatic weapons, improved effectiveness with automatic weapons, faster reloading with all weapons, and grants detection of cloaked specimens within a certain radius. However, use of the perk is not required for advancement, i.e. the Commando perk requires damage dealt with automatic weapons as a component of advancement, however, using an automatic weapon whilst being a Medic or Sharpshooter will still advance the Commando perk. The game takes place in London, England. Horzine Biotech,killing floor code,killing floor serial, a biotechnology company, is contracted to conduct experiments of a military nature involving mass cloning and genetic manipulation. Something goes horribly wrong during the process of the experimentations, and human subjects begin to exhibit grotesque mutations and disfigurement. They become increasingly hostile, and eventually overrun the internal security forces of the corporation. Hours later, the first waves of the specimens break out onto the surface, disrupting a peace protest outside the well-known military contractor. Despite the best efforts of local police, the civilians are quickly overwhelmed and consumed by the seemingly endless supply of clones now streaming from the gaping maw of Horzine Biotech's headquarter. Having escaped their sterile prison, killing floor key,killing floor cd key store,the creatures began to fan out to neighboring areas, devouring the helpless citizens of London while the Metropolitan Police bravely but fruitlessly attempt to stem the tide of mutated flesh now spreading across their city. Desperate to contain the outbreak, the British government begins to organize ragtag teams of surviving British Army soldiers and Special Branch police officers to fight back against the hordes of mutated "specimens" now running amok throughout the capital and its outskirts.,killing floor key code,killing floor cd. The player takes the role of an anonymous member of one of these teams as they partake in a variety of missions in and around the city of London.