Cat People (1982)

Revealing mistake: During the autopsy scene, it's obvious that the Panther is still breathing when it's supposed to be dead.

THGhost

Plot hole: We learn in the film that Cat People must kill a human in order to return to their human form. However, after becoming a cat at the swimming pool and terrorising Alice, Irena becomes human again without making a kill (the only other person at the closed pool is alive and well at the end of the scene - we know Alice has not imagined the presence of the cat because of her shredded clothes). (01:31:00)

ComicBoy

Paul Gallier: Long ago, our ancestors sacrificed their children to the leopards. The souls of the children grew inside the leopards, until the leopards became human. We were gods then.
Paul Gallier: We are a incestuous race. We can only make love with our own, otherwise we transform. And before we can become human again, we must kill.
Paul Gallier: Welcome home.

Paul Gallier: Did they ever tell you how our parents died?
Irena Gallier: Yes.
Paul Gallier: What did they tell you about me?
Irena Gallier: Well, not much. I knew I had a brother but I was only four. I used to fantasize about you when I was in the orphanage.
Paul Gallier: Fantasize?
Irena Gallier: Well, you know, about you coming to rescue me and things. Daydreams.
Paul Gallier: Yes, I had the same dreams.

Irena Gallier: I'm not like you.
Paul Gallier: That is the lie that will kill your lover.