Even as a 30-something myself, having that backdrop of the Heavy Metal magazine explained help me to understand why it had such a disjointed train wreck of a plot. Half the episodes I saw, I'm like, "WTF does this have to do with that big killer orb thingy?" Sure, it's supposed to be a collection of various evils that the orb has propagated over the millenia, but it's not very compellingly communicated. The whole movie plays out like a clip show.
But then, we're talking a 1981 movie. If you're 30, it was released when you were about 1 year old. So this movie is even older than you might think, any 35 year-old thinking back to the days when they were adolescents foraging for porn at the urgings of hormones should realize what they were really doing was scrounging for a decade-old movie that they hoped the adults had forgotten.
I never did get to see an uncensored version of it. But then, thanks to the wonders of the Internet, I'm sure I've seen Hentai that was about 50 times more explicit. Really, looking back at Heavy Metal, it seems like it was much more of a stoner movie, the music was mostly stoner music and it comes down to psychedelic drug use more than once.
[Whoops, didn't expect that youtube link would actually have some nudity. Removed link to establish there's drug use.]