Factual error: When Lt. Dunbar is being interrogated in the Commandant's office you can see a map on the far wall. It is a map of Germany dictated by the Treaty of Versailles which ended World War I because it shows E. Prussia separated from Germany and does not include the annexation of Austria and Czechoslovakia. These annexations were completed before the start of World War II in '39 and certainly before late '44, early '45 when the film took place. It is highly unlikely any German officer would have this map displayed not only because it's inaccurate but because it displayed the territorial losses brought on by the humiliating defeat of World War I.
Continuity mistake: There is genuine wartime footage of Spitfires of the the right type for the period, but other scenes have later (maybe even postwar) versions flying about.
Other mistake: Just after the Royal Navy destroyer has sailed through and depth charged the area where the British survivors are, there is a shot of the churned up sea with sombre music playing, and the seagulls are flying backwards.
Continuity mistake: After 1st Sgt. Milton Warden breaks the bottle to stop the fight between Pvt. Angelo Maggio and Sgt. James R. "Fatso" Judson, he throws the bottle in a corner. In the next shot, he's sitting down with the broken bottle on the table in front of him.
Factual error: When the captain of the Essen is interviewing Brown, he claims that "No British light cruiser captain would engage the Essen." In fact, history has shown that RN, RAN and RNZN captains could be depended upon to place their ships in harm's way against a superior enemy. River Plate, the Jervis Bay, HMAS Sydney, and Craddock at Coronel are ample proof of Nelson's influence..."No captain can do very wrong if he places his ship alongside that of the enemy."