My father called it one of the cheapest movies he had ever seen.... but when I saw it, I was a little kid, and it looked awesome, not cheap.
Now that I'm older and revisiting one of my favorite childhood films, yeah, some of the backgrounds move more than a Monty Python sketch. There is some obvious miniatures.
But... who cares, the story is really good. It's an adventure with loyal companions, an evil enemy, and a princess to rescue all in a sword and sandal sort of science fiction plot that tells a pretty good story even if it's a genre of adventure that we have seen over and over again.
It's just pure entertainment, and, if you are a kid, it's an epic film that you will love for the rest of your life.