Best WW2 Submarine simulator game I ever saw.
There is a sequel, however it takes a look at the Pacific Ocean rather than the Atlantic, and the association created by making a game about German submarines in this area immediately sinks us into the movie "Das Boot".
For 2005, this game has the most depth out of all the other naval simulations that exist, and there aren't too many of them, which is quite a shame.
The game itself, is easy to learn but hard to master, especially when enabling the realism settings, such as dud torpedoes, no external camera view (meaning that you are limited to the periscope which, in terrible weather really gives you a feeling of what it's like to be in endless ocean) etc. etc.
It's a game better played with a cup of tea, prepared for hours of searching for enemy ships or convoys, planning an assault and getting away (or maybe returning). It's quite simple.
But the idea - of making ships go to the bottom (that's very well detailed as well) simply grabs my attention irreversibly.
If you're into ships, this game is one you should try.
Although it's nearly 10 years old, a marvelous mod called "The Grey Wolves" breathes some life into it, while a small but friendly community on www.subsim.com keeps this legendary game alive and sailing.
I'd say it's quite sad that we don't get these types of games more often.
Also, yes - this is probably better than Silent Hunter V at least without mods (not many of them (up to today - 23/07/2014)).