The film's screenplay was based on the book How I Saved the World by Alexander Lullington-Smythe, which was published by Aphrodite Press in 1976 and was "very publicly discredited" in 1978. This led to the production of the film being shelved for over a year. A film critic for the magazine Film in Focus commented upon the film's release in November 1980 that it was far from being the "rational, methodical investigation into the events of 1965" which was required. He criticised the film's director, a newcomer named Anthony Jones, for buying "wholesale into notions of alien shape-changers and government conspiracies", which resulted in the film devolving into a B-movie.
The critic added that the film's "fair cast does its best with a script that veers from the turgid to the unbelievable". The veteran science fiction and horror star Peter Cushing played the lead role of "the mysterious government adviser, Doctor Who". However, the critic noted that Cushing's "endearingly eccentric professor [was] as fictional as the rest of Prey for a Miracle" as what little was known about the real life "Doctor" suggested that he was "a shadowy, manipulative figure".
In his final remarks, the critic opined that it "should have been a film about the nature of belief and about how it can distort one's perceptions". He lamented that the film could actually end up making this point as he believed that many people would see the film and regard it as an accurate representation of what had happened fifteen years earlier. (PROSE: Salvation)