Torpedorun

Your base is due to be attacked by several convoys of ships so you have been tasked to command a submarine and look for the convoys and destroy them. Starting from your base on a single screen map, you must sail around the surrounding waters looking for convoys either on the surface of the water or underneath. You are able to steer your sub as well as control the speed listening to your echo sounder. For a look at your location you can use your periscope to visually check but you can only be so deep under water before you lose the periscope if in use.

You only have a limited supply of fuel and torpedoes but a return back to base replenishes these. Sailing underwater decreases your oxygen levels but surfacing increases it as running out of oxygen means game over. Leaving or entering your base requires moving through an area full of mines and this is viewed from the side with the screen scrolling left to right. You must move up or down to avoid the mines or it is game over. Once you encounter a convoy, you can use your periscope to help you aim and fire your torpedoes. The ships will fire back and also planes escorting the ships will try to destroy you so diving allows you to avoid being hit but you get less points for hitting ships. If you hit a ships ammo store then it is an instant sinking but anywhere else only damages the ship.