These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Dark Horse: Evil Ed, oh so much. When his actor, Stephen Geoffreys, refused to appear in the sequel, critics considered it career suicide. They were right. He wound up making gay porn, though it appears he's moving back into regular films.
Evil Is Sexy: Amy, in the basement before her final transformation.
Regine in the sequel.
Foe Yay: Between Jerry Dandridge and "Evil" Ed. It's not subtle.
Freud Was Right: The entire film is about sexuality and growing up. Amanda Bearse does a yeoman's job of being convincingly a girl, and as the film progresses, she becomes more and more mature, until her appearance as a vampire, cooing, "What's the matter, Charley? Don't you want me anymore?" At that point, it's hard to believe it's the same actress. Ed goes through his own sexual awakening (thanks to Jerry) as well.
Nightmare Fuel: The makeup effects on Amy toward the end. Originally the effect Richard Edlund designed for the librarian ghost's One-Winged Angel form in Ghostbusters, but it was kept out of that film because it was just too frightening for it.
This also comes with a bit of Enforced Method Acting. William Ragsdale wasn't allowed to see Amanda Bearse's full makeup until they actually started shooting, and if you look at his face when she turns to attack him, you can see he's legitimately scared out of his mind.
The scene where Evil Ed shows up under the covers of Charles' mom's bed with a red wig, the wig's pretty narmy but the face gives a legitimate Jump Scare.
Also when he turns into a red-eyed wolf (a real one), and then after being stabbed through the heart by Peter, he slowly turns back into his human form, and by change I mean being that a near naked humanoid with a wolf's face that slowly morphs back into a human shape which looks disturbing and demonic at the same time and the the gurgle as he's slowly dying will leave an impact on you. In addition to the hand effect of solidifying back into a human shape as well.
Jerry's caretaker/partner who goes from Perpetual Frowner to Affably Evil in a nanosecond of his introduction, Also the fact that he was really hard to kill and wasn't even a vampire, but hinted to be a slime zombie monster as the graphic death scene of green slime and later sand gushing out of him and rapidly melting/decaying into a skeleton; and giving one last smile as it's satisfied that it managed to scare the shit of out of our protagonists.