This is a first-person shooter in which players engage in futuristic battles against invading aliens. Players use pistols, sniper rifles, machine guns, grenade launchers, and swords to kill enemies during frequent and fast-paced combat. Characters are occasionally impaled on glowing swords, and aliens can be seen stabbing fallen figures during some battle sequences. Gun fights are highlighted by realistic gunfire sound effects, explosions, and screams of pain. Human and alien characters emit spurts of blood when injured; players are able to shoot dead enemies, causing more blood to splash out. Blood is sometimes depicted on the walls and ground.