The campaign is played from a first-person perspective across linear missions with branching objectives and multiple environments. The main goals include eliminating Swarm creatures, rescuing personnel, defending locations, collecting mission items, and destroying alien installations.

Players move through combat zones, search for weapons and ammunition, activate equipment, and fight both small enemies and larger alien threats. The arsenal includes conventional firearms, explosives, and specialized weapons. Progression is mission-based rather than experience-based, with new areas and objectives unlocked by completing the current assignment.

Single-player missions are accompanied by multiplayer combat modes for Nintendo 64 players.

Conserve ammunition for specialized weapons and use the environment to create distance from groups of Swarm enemies. Search side rooms and dead ends for ammunition, armor, and mission-critical items before entering major encounters.

Identify objective markers and map routes before committing to a fight. Against large enemies, keep moving, attack exposed weak points when possible, and avoid being trapped in narrow corridors.