If you want to know what was going on in Los Alamos during the Manhattan project this is the film you should watch, not "Oppenheimer". This film is based on the autobiography of Stan Ulam who was actually there during and after the war ended. Ulam worked in the relatively unknown fusion bomb group headed by Edward Teller. This was a failure during the war so is not mentioned in most histories. This film accurately gives credit to Johnny (as he was known) von Neumann who was the person who was able to make the connection between theory and actual design of the successful bombs. Oppenheimer's main contribution was recognizing von Neuman's ability.

There are several errors even here. One while the stated rationale for making the bomb was to prevent Hitler from making it first. But the German physicists were way ahead of the Americans so knew that an atomic bomb was a very expensive longshot, especially for Germany who was fighting on many fronts. So they never tried. Thus this rationale was mostly hype on our part. But the scientists said nothing because this was a wonderful adventure in physics.

Another was that Tellers main rationale for his fusion bomb was that it was thought to be no radioactive and there would be fewer civilian collateral causalities. As it turned out the eventual hydrogen bomb built after the war was a hybrid, made mostly of uranium and plutonium, which gave the original bombs their lethal radioactivity, with only a small fusion reaction, again mostly for hype.

One error in the visuals is that von Neuman was shown before the Trinity test standing in front of his computer which had presumably made the calculations. Actually von Neuman had only recently come up with the design for the computer and was upset at being recalled to Los Alamos for the Trinity test because he wanted to start building his computer in Princeton. In fact he had at that time only one 20 year old physicist's wife with little formal math or physics background to help him with the calculations. Reportedly he told her that" he was inventing the computer to replace her because she was so bad at arithmetic." Actually it took 15 years before electronic computers were allowed to replace the "lady" computers, see the great film "Hidden Figures" for a good exposition of that.

Sadly this film was had a lower advertising budget so few have seen it, unlike "Oppenheimer". Accuracy is boring so it hard to recommend this film to non science geeks. But as biopics go, this one wasn't bad.

I thought the story was pretty interesting. But overall it was pretty slow moving. And the actors were all quite wooden and stiff. Almost no one showed any emotion in the whole movie.

The plot synopsis didn't help-It's not warmhearted. We watch the journey of a man from the beginning scenes as a creative teacher, loving brother and son who grows increasingly anxious as the Nazis move toward Lviv, his parents' home and the location of his college and friends. He is temporarily safe (no resident status) in the US with his 17 year old brother but feels he needs to do more for the war effort, and joins the Los Alamos nuclear team, bringing his wife, a French/Jewish refugee in danger of being sent back to wartime France (he is attracted to her, but also wants her safe from Nazis). The nuclear team finds the nuclear solution they sought, the war is won and the bomb is used on civilians, but Ulam has lost his family and college friends in Poland. (Later, he will lose his longtime team member and friend von Neumann to cancer, probably caused by atomic radiation at the bomb test site). Ulam is left in a dream state, meditating on earlier lost Native American civilizations like the Anansazi with the ghost of his friend...The non-movie Ulam probably felt the survivor guilt that his colleague Leo Szilard felt (My Trial as a War Criminal) but his family life continued and he formed new creative computer math teams. This biopic sort of presupposes familiarity with WWII and Cold War issues like US impunity from war crimes...