Not the most memorable film I have seen, however the constant saturation of sophisticated special effects (for the time) and the fads of the time that were haphazardly included in the screenplay seems to draw one in for the sheer kitsch value.
However, despite the esteemed cast, not one of the actors on this film could have rescued the abysmal script. The lines are stilted and unnatural for the dire situation the characters are in, and almost every character seems disinterested and bored. The impromptu trumpet dance scene with Barbara Eden and Frankie Avalon has no relevance or meaning whatsoever to the story.
Things became a tad off kilter in the underwater scene with the obviously fake sea creatures such as a propellor-propelled swordfish and a foam squid. Afterwards, people become ill and lenghty monologues about life and the end of the world ensue.
A somewhat forgettable sequence in an underwater minefield comes next, in which the most memorable thing aside from the blank, bored characters was when I spilt my can of soft drink.
However, like 'Mommie Dearest' or 'Giant Spider Invasion', I couldn't stop watching due to the unintentional humor and dreary plot twists. From that aspect it was watchable, even entertaining. Even the obvious scientific error of 'skyfire' in space posing a threat to earth became laughable after a while.
Despite the stilted acting, the dreary script, the factual errors, the laughable special effects and the irritating sound effects, the mediocrity of the movie makes it worth watching, however not repeatedly. No one should have to do that.