I never saw that cartoon. I didn't realize it was such a faithful adaptation. I'll try to track it down on YouTube.
Well, it wasn't hardcore, and neither is the DVD. Was the X-Rated version hardcore?I actually saw Flesh Gordon in the early 80s at a Drive-In near Hartford-- it was part of a triple feature of genre-related erotica, but I don't remember the other two movies.
It's quite possible you saw the R-rated re-cut, instead of the X-rated original.