This game was a pure delight ending the Cold War with a game about fighting WWIII sub battles. It was not easy but it was fun, especially when you managed to pull off a stunt that seemed impossible.
I vividly recall laughing uproariously in triumph as a young college freshman when I managed to play a Soviet Captain who ... well ... could easily have started WWIII with his dramatic actions, greatly exceeding the most famous of US sub captains in real life.
I never got to play all the missions because my copy stopped working long ago. I located an archived copy online as abandonware. It will not work on modern systems but I downloaded it anyway in hopes I could pay somebody to upgrade it, or in hopes I could find a museum piece computer from long ago, so that once again I could try my hand at commanding submarines.
The newer submarine games have grown advanced in the past 30years but they lack the feel and the gravity that you could feel in this original submarine simulator.