At the beginning of the movie, a sailor stops to salute the major. Sailors do not salute inboard a ship unless they are reporting to an officer on watch or reporting to the CO at Captain's Mast for non-judicial punishment (UCMJ Article 15).
The Destroyer (or battleship) that's how confusing this is,show sailors in dress uniforms not dungarees and helmets.Not a Navy officer in sight...
Regular German army soldiers did not wear Swastika armbands.
A red Massey-Ferguson TE35 tractor shown in the fighting scenes after 1 hour. The tractor model were in production first in 1956 to replace TE20 introduced in 1946 (grey)
And the "German" trucks in the same scenes are American Ford trucks from late 1930s.