There have been numerous productions that tell of the development of the atomic bomb. The Robert Taylor film ABOVE AND BEYOND (flag waving interservice propaganda really; if you believe this one you think that the Army Air Corps, in the person of Paul W. Tibbits, ran the entire show!), the NBC produced ENOLA GAY (probably A LOT closer to the mark), and the BBC-TV series, OPPENHEIMER, with Sam Waterston in the title role.
FAT MAN AND LITTLE BOY takes the same approach that the BBC series did but widens it; it avoids the "Gee Whiz" technology of the Manhattan Project and focuses on human aspects; the personalities involved in the work. Instead of focusing on Oppie, it covers a wide swath of mythical but pretty typical people who were part of it.
With reservations, Dwight Schultz did a good job as Oppie, presenting a dreamy, Ivory Tower academic who struggles to relate his contributions as a physicist to his inclinations to view the world in a wider social and moral context... only to have that struggle won by an overriding lust for personal power and glory. In THE DAY AFTER TRINITY it was made clear that Oppenheimer viewed himself as a "superior being" by virtue of his vast, wide ranging intellectual prowess. In the end that was Robert Oppenheimer's downfall; he saw himself as a sort of "Philosopher/King", a moral and intellectual superior who could (and rightfully SHOULD) "wisely" prescribe what was best for the rest of the world re. nuclear weapons development and deployment.
Unfortunately, wisdom doesn't dictate the actions of nations or direction of events on a global scale. Wisdom doesn't bestow temporal power. When it tries to exercise such nonexistent power (as Oppie found when he opposed the development of "The Super", the hydrogen bomb), wisdom is ignored and banished by those who REALLY have the power.
I found myself faulting Schultz character in one way; his Oppie exposes himself TOO closely and personally to the Manhattan Project, despite the doubts and fears that tore at his intellectual basis. The real Oppenheimer would have had to take a different approach; at the beginning he would have had to come to the firm resolution that the project would result in ultimate good. The ugliness it produced along the way would be an incidental price that must be paid to attain that ultimate good, and it must be ignored... at least until the end of the project when there was leisure to assess the gains and losses. Oppie clearly did that, and it resulted in his controversial postwar statements to the effect that science had now known sin, and that was a knowledge it could never lose.
While the project went on, such considerations HAD to be pushed aside if he was to maintain his sanity.
Because of this ambiguity, Schultz character comes off as a weak, frightened little boy who could NEVER have served as "Coordinator of Rapid Rupture", as Oppenheimer unofficially dubbed his post.
Paul Newman's take on Gen. Leslie R. Groves is fascinating, and a bravura performance, if possibly a LITTLE BIT over the top.
Groves was a civil engineer by training, but first and foremost he was a SOLDIER, and a general to boot! He's accustomed to DEMANDING that things go HIS way... intensely driven, a foul mouthed, spoiled child who has tantrums at the drop of a hat, who reveres his country and isn't too proud to fall on his knees and pray. In other words, very much like REAL (ie, NON civil engineer) soldiers, aka George Patton! Grove's MISSION not only comes first, it is his ONLY consideration... feelings and egos be damned, except for his OWN, of course!
Groves couldn't admit it, but he knew full well that he NEEDED Oppenheimer; military rank meant NOTHING in the world of theoretical physicists. Oppie was a necessary interface between the two worlds he had to straddle.
Again... I have to fault the script on this, and for the same reason.
In reality, Groves already OWNED Oppie; if he didn't, Oppie would never have been chosen for the post in the first place. History tells of MANY cases where other scientists, some as stellar as Oppenheimer, simply walked away from Groves recruitment efforts. At one point Groves was so desperate that he proposed DRAFTING the physicists he needed!
Groves attempts in the film to maneuver and control Oppie were UNNECESSARY... they only exist here as a dramatic device which indeed helps make the atmosphere of the film quite ugly.
Kusak's "Michael Merriman" is a composite of several real characters, but they're from a different time frame. Several research accidents similar to the one depicted happened in POSTWAR weapons research.
Merriman's radiation overdose creates another ugliness in the film, but one which is, IMHO, necessary, and pretty accurate. People with weak stomachs will have a hard time handling the hospital sequences; they're all TOO real.
The main idea that comes across, but not strongly enough IMHO, is the big truth of the Los Alamos experience. The scientists who signed on were young, idealistic and naive as well as talented. Most were on their first excursion out of the shelter of the campus. To them the project was a patriotic adventure that allowed them to practice experimental physics on a large scale without the constraints of budgets or "excessive" bureaucratic oversight.
It was not only their brilliance, but their youthful exuberance that produced the atomic bomb.
There's plenty here to make the thoughtful viewer intensely uncomfortable about this movie. Just the same, if you filter out the Hollywood BS (there isn't that much of it really), this is probably a pretty accurate view of the inside of Manhattan Project.