This 'aggressive infiltration' is at the heart of the game which sees a Russian missile complex taken over by a mysterious military faction. Taking on the role of US military operative John Cipher, gamers must regain control of the base before any of the nuclear warheads are launched.
Cipher took a bullet to the head in an earlier mission and had to be brought out of the resulting coma with experimental surgery that affected his adrenal glands, and it's adrenaline that fuels these devastating stealth kills. Therefore the trick is to manage the amount of adrenaline Cipher uses so he has enough to cope with any situation.
Cipher Complex is currently in development for PS3 and Xbox 360 with a release date yet to be confirmed.