Movie about assassination-attempts has a natural point to use as its climax: the attempt itself. It would not be easy to keep the ending surprising if the target is Adolf Hitler, and the year 1939. This movie thankfully does not attempt to build to the grand assassination attempt, but opens with it, and spends the rest of the runtime pondering: Who is this Elser guy? What did he do? How did he do it? Why did he do it? It does this by using the interrogations as a sort of frame, and then delving into episodes from Elser's life. It does not attempt to tell his entire life story, but rather pick scenes helpfully to understand the state of mind he was in during that pivotal moment in 1939.
This is an interesting story that is very much worth telling. Elser seems to be an extraordinary character, and it's one of those moments in history where everything could have been completely different. The movie has taken some shortcuts though, as is to be expected. Elser is shown as both a clever, talented man (as he was), but at also with some faults. He is shown as almost apolitical, which makes for an interesting character, but the movie would have been better if they had explored what is known about Elser's actual relationship with Nazism.
Over all it is a movie worth seeing, even though it is easy to be bored by all of the movie about the brave men who fought Nazism, as they often spend very little time on how Nazis also were people. Good vs evil is a misrepresentation. That said, this movie handles much better than many other movies with similar subjects.