The title says it all, I feel like I can really get into a movie when I know that it stuck well with the source material, I feel like this is a pretty safe place to ask the question since these films could be considered a form of historiography.
hi! movie recommendations are always a popular topic around here; more are welcome, but meanwhile get started on our stockpile of some previous posts in the FAQ* - there are some posts just on war movies, but most posts are wide open so you'll have to dig a bit for war stuff
*see the link on the sidebar or the wiki tab
If you don't mind subtitles (or speak fluent German) Das Boot is quite good. It is about a WWII U-boat crew on patrol/attack in the Atlantic.