As the admiral of an Omega class sub during WWII, you're charged with underwater reconnaissance and demolition -- which means you seek out Nazi subs and sink them before they sink Allied ships.
Avoid floating mines as you quietly creep through the ocean, avoiding the enemy ships
Use your deck guns for anti-boat and anti-aircraft combat
Track down enemy subs & shoot them out of the water with your torpedoes -- but be sure you've flushed them all out, or you'll reveal your position and be open to attack!
Incredible multiplayer action through a LAN or Internet