What jumps out at me here is the second panel on the left side of the page where the two main characters are dressed in outfits from Outland, walking through a hallway from the end of Empire Strikes Back. My kneejerk reaction is that this guy is mixing his visual references. At this point, though, this should be called Space Opera, not Rock Opera.

(Heavy Metal issue #77, August 1983 – Page 92 Rock Opera by Kierkegaard)