A great submarine sim.
The difficulty level is just right and can be adjusted with greater realism as you become more accustomed to the controls and what is expected of you.
Some of the aspects of the game are little tedious. There is time compression to save you having to wait a week to travel half way across the Atlantic but perhaps a little more compression would be good. Crew become fatigued with time and you have to keep your eye on it and having to move crew members into the bunk quarters and the rested crew into places where they are needed becomes a bit of an annoyance and it would have been nice to be able to automate it.
To summarise, this is a very very enjoyable game that can be played more like a simulator or more like an arcade game (by reducing the realism) which gives it real longevity. Great value and much better than the newly released SH5.