(*Disclaimer: I've never actually seen this movie so bear with me.)
Two guys are fighting in this futuristic world, where swords are made of lasers and they're fighting to the death because one is really evil and the other is good. This happens. The evil dude is wearing a black suit with a funky black respirator type helmet. Some stuff happens and the good guys is all like "you killed my dad!" to the evil dude (major paraphrasing here). The evil guy replies. "No,
I am your father...you know what forget it."
Twist are not secrets, secrets are wasted on stories because if you keep the secret then what was the point of having it in the first place? The world of the story is only constructed out of they idea's portrayed so if you have an idea do tell or else nothing is gained.
Now you can have twists in a story, which are like secrets but not really. The difference between a secret and a twist is that a secret is something nobody knows. Whereas a twist is a plausible end, road less traveled that people ignore until they can't ignore it any longer. i.e. a twist is always there, your job is to make it so people never think about it until you want them to.
The reaction to a twist should be:
"Oh! how did that happen?" and then as they look back on all the events leading up to the twist.
"OMG why didn't I see this coming?"
Whereas if you tell someone a secret, their reaction will be:
"I'll take your word for it."
As there is nothing to look back on to support this new information because it was a secret.
Twists answer a question that may have been raised or fill a gap. For example your main character never had father and the villain had a son. Now people are not going to generally put two and two together to equal four when the two's are so terribly different (rivals). But if they were so inclined as wonder about the coincidence the evidence is there. Twists are not without basis, they are something people would've never guessed but they are not with out basis.
How this helps