Really long. Overly dramatized normal happenings for plot suspense and tension.
I’m lucky in that I am already somewhat familiar with some of the characters depicted (Niels Bohr, Heisenberg, Enrico Fermi, and Edwin Teller). Without that knowledge, viewers will be lost to much of the subtleties.
The time shifting, out of order plot and frequent switching from color to B&W will be confusing to many who don’t already know the story.
Fine acting. Very believable characters.
If we still had Bockbuster, I predict you would find it in the bargain bin within a year.