If I'm being honest I wasn't too keen on watching the directors cut. But after finishing, I cant really imagine it being anywhere under 3 hours. One of the most incredible war films I've seen.
I've seen Claustrophobia done well in films (Rear Window, the first hour of High and Low, Alien), but never like this. Everything is done with close-ups. Even after spending so much time in the submarine, you never really get your bearings, it's very confusing. In the action sequences, it becomes expressionistic. Handheld shots give us so little. Only flashes of light, and men running up and down the length of the submarine.
This is now my third favourite war movie. Come and See > Apocalypse Now > Das Boot