Most science fiction films are big on ideas and special effects, but weak on coherence and character development; most horror films are just the same, except without the ideas. But David Cronenberg's 'The Fly' takes one simple idea, develops it properly, and eschews (its genuinely terrifying) special effects until its truly horrific climax. And by paying some attention to the personalities of its protagonists, it actually makes you care about them (Jeff Goldblum is excellent in the lead role), and adds a level of serious reflection on the very nature of human mortality to the raw shock. The mix amounts to a gruesomely good film.