1960 is a great year of suspense films, with two great movies made by two great directors - Alfred Hitchcock's Psycho and Michael Powell's Peeping Tom.
Heartthrob reminds me of Peeping Tom, except I have sympathies for Tom, an abused child who developed as a psychopath and committed suicide the exact way he killed everyone while I find it absolutely absurd to show sympathy to Heartthrob's Henry.

This movie is based on the feelings of his obsession to this girl, Sam. The beginning of their relationship begins with a conversation of arguments, later dishonesty and obsessive murderes and surveillance.

Henry is absolutely head over heels of this Sam, and he even in one scene tells her mother how easily he can use the cup to kill her. His killings are easy, simple and we never see any counter attacks by the victims or police investigation, because according to the director, he's the smartest person.

When we approached nearly to end, we see Henry has bound her mother to a chair in the other room for whatever reasons and he, then, invited his love. She somehow discovered her mother, then she helped her mother to escape and we see a scene in the end.

I do not see Henry as a smart character anyway, rather a dishonest, disloyal and pathetic obsessed murderer and in Sam, I see a selfish person, who continues to love him because she was being obsessively loved by a teenage murderer, and she ignores all her friend's deaths and lacks a serious conscience.