Nightbreed (1990)

Continuity mistake: During the final fight between Boone and Decker, right before he is killed, Decker almost falls backwards off a small "cliff", only to be caught by Boone. Watch the shots closely. In the first shot from above, he teeters on the edge, about to fall, and Boone isn't holding him. Yet in the next shot from below (looking upwards), Boone is holding onto Decker's shirt/jacket. The camera cuts back up above, and Boone is no longer holding Decker, but instead grabs him while shouting "Not yet!"

Trivia: The post-production process of the film was very dramatic. The studios became worried that the subject matter was too strange for audiences, and in an attempt to make the film faster and simpler to understand, they demanded that nearly an hour of material be removed from the film. Director Clive Barker also maintains that the film wasn't marketed properly. A Director's Cut of the film (containing much of the cut footage) was announced more than 20 years after the film's original release-date.