Probably the best WWII sub movie ever made. The difference you noted between the XO and the other officers, particularly the CO is actually quite accurate in terms of portraying the difference between the Kriegsmarine leadership in general, and the Nazis specifically Hitler. One thing you might notice in a lot of footage taken from WWII, the Kriegsmarine generally maintained the traditional military salute instead of adopting the Nazis salute. Furthermore, political discussion and involvement was generally frowned upon by the more veteran officers especially when it dealt with the Nazis party. A prime example of this was Admiral Günther Lütjens, who sadly is portrayed disgustingly inaccurately in the movie, "Sink the Bismarck". The movie portrays him as a Nazis zealot who had a grudge from the first world war. In truth he was openly opposed to many of the Nazi's policies and deliberately refused to render the Nazis salute during Hitler's visit to Bismarck. My understanding is that Lütjens also wore the old Kaiserliche Marine dagger with his uniform as opposed to the Kriegsmarine dagger of the time. The main difference being that the Kriegsmarine one had the swastika on it.
Another thing that Horatio points out about the CO and many of the other officers feeling like they were merely cannon fodder, probably isn't far from historical truth either. The naval leadership at the time had originally expected that war would not break out until around the mid 1940s. This was because the German navy was practically non-existent. Even with all the U-boats being deployed throughout the war, the North Atlantic was still militarily dominated by the Allies. Germany had no real fleet to speak of. There were no carriers, only 2 battleships, and a maybe a dozen or so cruisers of various sizes and maybe somewhere on the order of 50 destroyers (battleship numbers are kind of iffy because the classification of at least 2 ships as a battleship or battle cruiser is up for debate). Compare that to the Royal Navy with 15 battleships at the start of the war with more under construction, 7 carriers, 66 cruisers with more under construction. over 180 destroyers with more under construction.
The German Navy was under the understanding that Germany would not go to war until the fleet had been rebuilt. However, for reasons that will always be debated, Hitler went to war in 1939. over half a decade earlier than what had been promised to the navy. Ships like Schlachtschiff "H", which would have been the German equivalent to the ships like the USS Missouri or the Yamato sporting anywhere from 16-20 inch guns, ended up being postponed until the presumptive German victory in the war so that the resources could be diverted U-boats and other projects. The result was a navy that literally had no ability to take on the allied navies in a direct confrontation with any hope of victory.
"Don't confuse facts with reality."
-Robert D. Ballard