This is a first-person shooter in which players assume the role of an elite soldier who must stop supernatural events from bringing about Armageddon. Players use machine guns, shotguns, sniper rifles, grenades, and mechanized battle suits to kill mutant creatures and human soldiers in frenetic combat. Battles are generally highlighted by screams of pain, realistic gunfire, large splashes of blood, and slow-motion effects (i.e., "bullet time"); some attacks result in dismemberment or decapitation that leave body parts and bloodstains on the ground (e.g., mutants bursting into sprays of blood, soldiers' heads exploding from telekinetic attacks). During the course of the game, one female character is briefly depicted with exposed breasts, though no details (i.e., nipples) are shown. The words "f**k" and "sh*t" can be heard in the dialogue.