This was on TCM last night...thoroughly enjoyed it. WARNING: Spoiler
This came out during the time period it depicted; the middle of WWII. Ben Mankoweicz (sp?) informed viewers that this was a propaganda film that the War Office asked MGM to make.
If this is true, the producer hit his mark. I was very moved by it; the Nazi's looked very much like the sick, evil pigs they were (are?) especially convincing was Peter Lorre. I actually cheered when Kelly stuck a scalpel into his neck and threw him out of moving truck. The last scene was also very powerful; an entire village in France willing to burn down their own homes; "scorched earth" so that the Nazi's wouldn't have anything to plunder (which they would have undoubtedly done when reinforcements arrived to find a bunch of dead Nazi soldiers.)
I'd see this again.