Jerkass Woobie: Vance may be a batshit crazy Serial Killer with ridiculous sensibilities, but as you get the sense of how deep his sense of loss is, it's hard to not feel sorry for him.
Moral Event Horizon: Kent killing Joey by setting him on fire, something he takes obvious sadistic pleasure in doing.
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 Unintentional 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.
They Wasted a Perfectly Good Plot: This video review by YouTuber lampyman101 suggests that the film could've made for a genuinely good psychological drama if it had focused more on story and characterization and less on the sleaze.
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.
The remake:
Ass Pull: The killer turning out to be a somewhat poorly explained supernatural monstrosity.
Hilarious in Hindsight: The original was a cash-in on the original The Texas Chain Saw Massacre, which Tobe Hooper, director of this film, also directed.
Squick: Nell finds a trinket in the wall filled with bloody teeth, which looked like they were wrenched out.