I really enjoyed the movie. All 3 hours of it. I had not sat in a movie theater since 2018 to watch "BlacKkKlansman." My mind had apparently become spoiled by home viewing, as it kept worrying that I would have to leave to use the restroom and miss something good. At home I could just hit "pause." Thankfully, my bladder behaved and I missed nothing. Does the scene where Oppenheimer reads the Bhagavad Gita to his topless lover appear in the book in any way? If not, that scene felt a little unnecessary and just an attempt to insert some hoochie into the film. I was hoping his reading of that passage would have a different context, more related to the detonation of the atomic bomb. Also, Oppenheimer famously read what some called "his own idiosyncratic translation" of the original Sanskrit. It's a small point and it didn't ruin the movie for me, but that was the only time the movie felt a little off for me.
Some early reviews I read said that the film did show graphic footage of actual Hiroshima and Nagasaki victims. But none appeared in the version that I saw. If they originally appeared in an earlier cut and were then removed, I think that was the right decision, mostly out of respect for the victims themselves. Though some have argued that showing such things would have really driven home the horror of what Los Alamos had created. It's hard to say. Good arguments seem to exist on both sides of that question. The film did delve into that territory somewhat during the pep rally scene. That worked fairly well.
A now deceased relative of mine served on the Manhattan Project. He was stationed on Tinian Island, where the Enola Gay departed from with the bomb. He said absolutely nothing about his involvement until just before his death. My family history contains a lot of false lore, so I was skeptical until I actually found him listed on the Manhattan Project website. His daughter has since unearthed a lot of packed away materials relating to his involvement.