Sergeant Dennis Riley, a member of the elite United States Marine Team Red Light, receives a distress call from Fort Stewart, a top-secret research outpost in Antarctica, on December 24, 2005. The signal calls for an immediate air strike against the base. The team is dispatched to investigate, but their plane crashes in the tundra. When Dennis arrives at the facility, he discovers something terrible has transpired. He is forced to battle for his life as he fights mutated monsters and risks becoming infected himself.
Extermination is a horror survival game. The player character has limited ammunition for weaponry, and it is often best to flee from creatures. In addition to the standard health bar, Dennis has an Infection Rate, which increases progressively when attacked by animals. When his Infection Rate reaches 100%, he gets highly frail and mutates into a monster. MTS vaccinations can be used to combat infection.
The primary weapon of the player character, a particular purpose rifle, can be upgraded with modifications such as a zoom scope, flashlight grip, radar, and parts that convert it to other weapon types such as a flame thrower or shotgun, or rocket launcher. Dennis is also skilled with a knife. Batteries must be collected and utilized to activate various machines and save the game throughout the game.
