Good film, it feels quite realistic.
It is a shame that they tried to include some particularly interesting stories but didn't have the time to develop them, e.g. Feynman explaining to the high school interns what they were actually doing. These are referred to only in passing, and likely won't mean anything to someone who hasn't read the book.
The film settings are particularly good, and give what feels like an authentic view of the times. Particularly memorable are the Indian caves shown the film. TODO name? Possibly Puye Cliff Dwellings. Puye apparently appears prominently up on another film about Los Alamos: The Atomic city (1952). It is relatively close to Los Alamos, about 30 km away.
The title is presumably a reference to infinities in quantum field theory? Or just to the infinity of love etc.? But anyways, the infinities in quantum field theory theory come to mind if you are into this kind of stuff and is sad because that work started after the war.
Video 1. Infinity Trailer (1996) Source.