I've read the book (but haven't tried the game). I liked the book, although I did have problems getting past the premise (modern-day Germany begins a naval war with America and Britain, in order to sell diesel subs to a Middle East country in violation of UN arms sanctions. And, the U.S. President only lets the Navy use a handful of surface ships against the German subs -- no P-3s or SSNs -- just to keep the fight 'fair'
)