You start the game with
three submarines. Guide your submarine with the mouse pointer. Press the
mouse button to fire a torpedo upward toward the surface. Press the keyboard
space bar to fire a torpedo to the right. Since it takes your crew some
time to reload the torpedo tubes, you are allowed a maximum of one torpedo
at a time in each direction.
As the submarine captain, you must destroy all ten of the merchant ships
in the top row before you can move on to your next mission. Try not to
torpedo hospital ships. It's a violation of international law. Skillful
maneuvering will be necessary on advanced missions in order to survive
exploding depth charges, hostile torpedo fire, and magnetic mines.
Your sub has a limited supply of fuel and torpedoes, and must be resupplied
frequently. A supply sub will pass by occasionally near the ocean bottom
and release a trained dolphin carrying fuel and torpedoes. By making contact
with the dolphin's supply pack, you can resupply your vessel. Whatever
you do, don't torpedo the dolphin!