A weak specimen found in all waves.

Either the easy mode of difficulty (All specimens gain 5-70% stat declines.), or a player who's new to the game. The two are often found together.

A perk class selectable by the player character which specialises in melee combat.

A large specimen that can make its appearance on the first wave.

How much money killing any given specimen will garner, in British pounds. Varies between specimens and difficulties.

a perk class playable by the player character, specialises in using assault rifles and intelligence gathering.

A weak specimen found in most waves, usually considered a nuisance.

An action performed when Control is pressed (Default Key) causing the player to crouch and prevents the player from falling off edges along with a reduction of speed.

The amount of damage a weapon or specimen can inflict in a second, not always counting for reloading or other downtimes.

A state of being that players and specimens occupy once all of their hit points are depleted.