- Awesome Music: Sammy Hagar, Cheap Trick, Grand Funk Railroad, Blue Öyster Cult, Devo, Riggs, Black Sabbath, Don Felder... the list goes on. And that's saying nothing of the excellent orchestral score provided by Elmer Bernstein (unusually for the time, there was a separate score LP released alongside the song album; the complete score was later issued on CD).
- Harsher in Hindsight: The Captain Sternn segment is a lot harder to watch in the wake of the Colonel Russell Williams trial.
- Hilarious in Hindsight:
- The spaceship in "So Beautiful, So Dangerous" looks an awful lot like Kirby.
- The opening scene of a car in space became reality in February 2018, when Elon Musk and SpaceX launched a Tesla roadster into space with their Falcon Heavy rocket.
- Hype Backlash: The film is a perennial Cult Classic, but popular opinion has been steadily turning against it in recent years. There is much more adult-oriented animation available today than there was in the 1980s, and now that Heavy Metal has finally received a video release and it's no longer immensely difficult to find, people end up disappointed with the writing and tone, and some are put off by the gratuitous gore & nudity. That said, most people still agree that the soundtrack kicks ass.
- Genre-Busting: It's an animated sci-fi/fantasy/horror anthology movie. Whether you think it's good or bad, you have to admit there really isn't much else like it.
- MST3K Mantra: Since there were so many problems with production, the movie relies on the mantra a lot to make up for the plot holes and lack of continuity.
- What An Idiot: Harry exchanges the Loc-Nar to a mob boss. The Loc-Nar is shown to melt one of the workers who discovered it and is now safely encased in a protective capsule.
You'd Expect: The mob boss to leave it in its casing.
Instead: He opens the case and picks up the Loc-Nar, which melts him.
- The Woobie: The poor little girl in the bridge segments who watches her father be melted away into nothing before having to listen to the Loc-Nar share its history of destruction, all the while being told she will meet the same fate.