Right as the last Harry Potter book was being released, and everyone was panicking about the ending being leaked, a site called SaltyStix.com ran a story called The Best Twist in the History of Film (that I wasn’t shocked by at all). The best surprise ending in all of film history, according to this site? The Empire Strikes Back, and its revelation that Darth Vader was Luke’s father.
“It doesn’t even strike many of us today as something that could have ever come as a surprise,” writes Stix contributor Bob. “It’s kind of a shame to (sic), because I feel like when it was revealed in 1980, it shocked audiences around the world….Many people today don’t even realize that this was a twist at all. The idea that Luke’s father is Vader has become engrained in our social consciousness.”

As this site also points out, Empire was such a great movie, it wouldn’t have ruined the experience if you knew the ending before you saw it. “Far too many movies today are build on the idea of a twist ending,” Bob continues, “and some of these movies are completely ruined if the ending is known going into it.”
It’s true that some films dangerously hinged on whether the ending worked or not. A twist can totally make a film, like The Usual Suspects, and a film can also fall apart if the end surprise is weak, like the endings of The Game, Unbreakable, and The Village.

What The Sixth Sense had going for it was the fact that it came out of nowhere with no advance hype in what’s usually a dumping ground for Hollywood, the month of August. Once the word got around there was a secret, the audiences were very good about keeping it because the movie played fair.
The Sixth Sense was clever because the twist would have been easy to guess, but M. Night Shyamalan did a good job distracting you. Sense and Suspects also gave you a lot of clues along the way you didn’t notice at first. The most obvious one in Sense was Bruce Willis always wears the same clothes, and one of the best clues you’ll notice the second time you watch The Usual Suspects is right before Kobayashi comes into the story, Spacey is staring right underneath Chazz Palminteri’s coffee cup.
In both the case of Suspects and Empire, the twists were in character’s names. Vader means father in Polish, and Keyser Soze’s true identity was hidden in his name as well. At a screenwriting seminar for Fade In magazine, Suspects screenwriter Christopher McQuarrie recalled the character was originally going to be named Keyser Sume, who was a real person he used to work with at a law firm. Using a real name could cause legal problems, so it had to be changed.
McQuarrie’s roommate had a Turkish-to-English dictionary, and he exhaustively searched for a substitute last name. After looking up every evil word he could think of, like fire and devil, McQuarrie finally told his friend to look up the word verbal, which translated to Soze. McQuarrie then joked that the movie’s a huge bomb in Turkey.

