I thought Oppenheimer was mostly pretty riveting (my wife did to) — and walking out, I left wanting to see it again in another week or two (but never did).
And I’d gone into it half dreading a 3 hour film on the Manhattan Project (especially after work, since I work weekends now) — but the only time I glanced at my phone to check the time was shortly after the point in the film after the bombs had been dropped… and I was actually relieved(!) that there was almost a full hour of the film left! — and the last hour was as riveting as the first two, imho.
I saw someone mention online that you see very little actually being done in the film… that it’s almost 90% dialog and very little ‘action’. But I thought the film demanded my attention and kept my interest pretty much throughout (or at least 80% of the time).
Also, I haven’t seen much Robert Downey Jr. — mainly Chaplin over 30 years ago, and 2-3 other films he had smaller parts in (all back in the 90’s). But based on Oppenheimer — I will absolutely go see any ‘serious’ film he’s in from now on (especially anything that’s a period piece).
I also hadn’t ever seen any Christopher Nolan films — other than his first Batman film (which was fine for what it was — maybe the only Batman film I’ve ever seen, come to think of it) — but I need to go back and see some Nolan stuff at some point too.