The circumstances and the issues as presented in this film are very accurate--- maybe too accurate for commercial success, because many viewers may be displeased at the depiction of the German population in the aftermath of WWII. As far as the postwar vigilante killings of Nazis and the course of "Plan A" itself go, the film is again quite accurate although it simplifies the narrative by skipping past some complexities. And, strangely for a movie called "Plan A," it never mentions that there was a Plan B (less sweepingly murderous) and even a Plan C (even less so than Plan B).
I found the visual aspect very impressive. More than once, I marveled that a scene looked exactly as I'd imagined it from reading the history.
The writers and actors seem able to throw important questions out at the audience while still maintaining a feeling of naturalism. My one complaint there is that when someone is asked why the Jews didn't mount more resistance against the Nazis, the movie doesn't provide as full an answer as it could have.
And although the actors gave their all, someone decided to add drama to certain scenes by overdubbing some shivery breathing that the actors obviously weren't really doing. I had to say it. But that said, the movie presents an important episode-- we are still affected today by what, in the end, did NOT happen then-- and treats the attendant questions with due seriousness.