tipsfromchip’s review published on Letterboxd :
I never watched the TV show, so I was not coming into this as a fan. Then the movie they picked as "one of the worst of all time" turned out to be one of the better science fiction films from the 1950s (This Island Earth). I stopped watching this and went to see the full version of that first. I then came back to this and I could see how they had completely bastardized the movie to try to make it look as bad as possible, cutting whole sections out of it so the story made no sense. Finally, the jokes and quips just weren't that funny.
I read more about this movie afterwards because I couldn't believe the TV show had had such a cult following if the movie was anything to go by. Apparently, all involved hate the movie. One of the MST3K people, when asked what the worst movie ever featured on the show was, replied "Mystery Science Theater 3000: The Movie."