It was... OK?
Cillian Murphy is great, but I thought that Oppenheimer was going to be a little bit more charismatic and cocky. What we got was a bit of a "misunderstood genius" who's passion for his subject inspires those around him. Granted that may be my own fault for basing my image on Oppenheimer on the little I had read about him on beforehand. In any case, the strength of the film lies in the subject-matter and the good performances from all actors involved. Based on this alone the film couldn't fail. The events are simply too interesting for that.
I do not understand the people who told me that it feels much shorter than 3 hours. It very much felt that long, if not longer. The film never stops to breathe and forces you to stay plugged in. The dialogue is constant and relentless and when it's not, your ears are blasted with sound effects and background music. But despite throwing all of this at the audience for 3 full hours the end result still feels a bit hollow. It does so much and so little at the same time.
I did not find Nolan's dialogue to be as obnoxious as usual, which is quite some feat considering how much dialogue there is in this film. But that first sex scene was really awkward