Really, really splendid work.
The highlights for me were the save game problems, cutting back to Ubi, (didn't save the game in time) and of course, that superb lag sequence on the periscope.
I don't know if I'll be able to watch Das Boot anymore without laughing.
Edit Oh, and how could I forget, at the start when the chap in the car races over and shouts to them about sending back their save games. That was inspired.