I watched this film (unriffed) two days ago on Amazon Prime. I enjoyed it so much that when I found out it was recently "riffed" on the Netflix Mystery Science Theater 3000 The Return show, I watched that as well. What I realized was the version on Amazon has a dark ending while the one riffed on Netflix has a happy ending. So, the film was made with two endings. The version used on MST3KTR is also cut short in dramatic scenes, I'm not sure if that was edited by the comedy show or if the nice ending version was also presented that way. Besides the very different endings, the scene with the rocket ship is also much shorter and less dramatic in the happy version. There are other scenes that seemed different as well. I rate the dark ending version that I watched a 9. It's full of very dramatic scenes, I was really surprised. One reason may be it was filmed by later famous cinematographers, Vilmos Zsigmond and László Kovács. Another reason why I enjoyed this film is it has Playboy centerfold model, Delores Wells (hot!). It's cheesy at the start but gets pretty good later and the dark ending version is memorable. As far as riffing goes, this was the funniest MST3K TR episode I watched, but then again its not that hard to make fun of Danny.