I have played Silent Hunter 4 more than any other game on Steam. I was obsessed with it, played it every waking hour. Read up on Submarines. Watched the six-hour cut of Das Boot twice.
I would describe it to non-submarine nerds as a slow-paced stealth game. Very methodical. You can even calculate the trajectories for your torpedoes yourself, in what becomes perhaps the most compelling educational math game of all time. The game is very narrative, and open world in nature, though said world is almost entirely endless sea. I have hounded Japanese ships off the coast of Alaska, hiding in the fog as I used hit-and-run tactics against no fewer than five enemy destroyers, ever wary of their lumbering shadows in the mist. I have stalked convoys for days on end, slowly whittling down their numbers. I have used daring tactics to great success, narrowly avoiding the avalanche of depth charges from the surface. And I have used safe, time-tested strategies only to find myself sliding into a watery grave.
The game is tight as ♥♥♥♥.