Use the vampire jetpack to fight aliens! The jetpack runs on human energy so you must periodically pick up new life in order to maintain altitude. Each human type you pick up has a unique attack ability.
You are the last surviving member of a SEAL team sent into Russia. Fight off waves of invading enemies and survive for as long as you can. Start out with a pistol and a few grenades, but scavenge new weapons from fallen enemies to build up a deadly arsenal.