The reason the titles of movies are often completely different in Spanish is that a direct translation of the English title wouldn't necessarily communicate what's desired to a Spanish speaking audience.
Sometimes they translate well directly, but sometimes the title wouldn't be meaningful, or worse, repulsive. It's about correctly marketing the movie to this audience.
Sometimes it's fun to try to figure out how the hell (or why) they come up with the new title, I do admit.
When my partner becomes completely flummoxed with a movie title in Spanish he goes to the imdb (independent movie database) website. By entering one of the stars names, he can click on that actor's film biography. It lists all the films that person has been in by year. Since the channel guide lists when the movie was made, he can usually determine what it was called in English. Bit of work, but it works.