This is completely laughable film. Ridiculous from start to the end. Written by Hubbard pre-Dianetics, this is free from the pernicious influence of that mind killer.
The entire premise is soft sci-fi to the extreme. Humanoid aliens have tech to teleport matter across planets, wiped out the entire human resistance in minutes BUT keep humans as slave labour to mine gold with pickaxes (!!!). They are unable to alienform Earth’s atmosphere and have to live in a big glass dome. Note they went as far as building a glass dome but think Earth is an ugly-ass planet. Some human prince gets captured by the baddies and is subject to an intelligence ray that leaves him with an IQ of 100. He then leads a revolt that ends up with the aliens having their home planet NUKED. NUKING the planet makes it explode, Alderaan style. A synopsis that could as well be used in a parody to this film.
As for more down-to-Earth matters, everybody SCREAMS for some reason, like they are enacting a play for a giant crowd. Plus, there is literal cackling in a film that was supposed to be serious. Seeing Travolta dressed as a bozo cackling like a maniac make it impossible to take this seriously. It’s not so bad it’s good, it’s just bad.