The murders, especially due to the basic, almost nonchalant way they're filmed.
When Vance first dons his ski mask, it's slightly askew, giving this weird Uncanny Valley effect, plus there's Laurie's completely off the top of her head description of the afterlife, essentially an And I Must Scream scenario.
Took the Bad Film Seriously: Cameron Mitchell portrays Vance as if he's in an Oscar Bait character drama rather than a sleazy exploitation flick. As such, he manages to make the character somewhat sympathetic despite his horrendous actions, something which is no easy task.
What Do You Mean, It's Not Symbolic?: Seemingly promiscuous women are violently murdered with extremely phallic makeshift weaponry. In order, they're drilled, hammered, screwed and nailed.