Welp, the movie I was hinting at was "Cry Wilderness", a movie I'm only aware of because of MST3k.
Mine was "Alien" so Battlemaster discarded the right answer.
Freudian nightmare, as in a dark mirror ---> Alien has been described as a movie full of freudian fears and perversions (the Alien spying on Ripley at the end while she undresses), with everything surrounding him being a dark mirror of our reality (Organic vs. Technologic...)
Genders reversed, bones on the outside ---> it is a male astronaut that is "raped" and impregnated; the Alien has bones on the outside - another example of "dark mirror".
Parasites infect flesh and machines ---> Kane is infected by the chestburster; the Alien "infects" the Nostromo.
In the dim glow of lovecraftian stars. ---> "Alien" is considered one of the best lovecraftian stories ever made; the stars in its universe are distant and remote, whereas the bright and plentiful stars in "Star Wars" suggest a vibrant universe full of life.
The connection with "Heavy Metal", however, was a bit trickier. It was with
"B-17", the episode written by "Alien"'s writer Dan O'Bannon, and that be described, too, with my verses (check it if you are unsure). "Genders reversed" is the only tricky line for "B-17": at the end, in the planes' graveyard, you see Amelia Earhart's plane - with Amelia becoming famous for what was then a mostly male role.