Is there a characteristic way you feel movies get military engineering wrong, or is it just the usual handwave of convenient science is convenient, now (if the movie is intelligent) move on to the worldbuilding?

Anyway, movies always fail to consider how much machines would really weigh, or how much fuel they'd consume, or how much they'd cost. And while I had to sit down for about twenty minutes to work out the precise details of how wrong the math was in this particular instance, I have enough engineering intuition to have noted, while watching the movie, "there's no way the numbers here add up." That's okay though. Good world building and emotional arcs make up for bad math.

they appeared and they were such perfect types of scientist in a science fiction film (terminally tightly wound boffin, manically reckless geek)

Yes! Their interactions -- with each other, with their equipment, with the military -- all rang very true to me. I worked for two summers with Air Force Research Labs, and another year and a half with a defense contractor, and all those interactions rang very very true for me. They were perfect.