The great movie plot twists rank among the most unforgettable moments from film history. Janet Leigh's shock early exit, it was Earth all along,"I am your father," he's been dead the whole time! All great surprises that add whole new dimensions to the films in question, cementing them as classics.
Of course, sometimes accepting a twist means taking a lot on faith. Let's face it, the revelation of Luke Skywalker's parentage in The Empire Strikes Back does rather come out of nowhere and if you think it all through logically it makes very little sense that Vader would reveal it at that point, without having done anything about it in the years prior.
Still, while in the case of Star Wars we can suspend disbelief just a tad, there have been other attempts at big surprise plot twists that really don't stand up to closer scrutiny. But even when a twist doesn't necessarily turn the whole film on its head, sometimes they're just too misjudged to take seriously.
Sometimes, such creative decisions can be dismissed as a minor misconception, other times, they sour the film completely.
10. Laurie Is Michael's Sister - Halloween II
The Set-Up: the 1978 original established that homicidal maniac Michael Myers breaks out of a mental institution and returns to his hometown of Haddonfield to go on a killing spree, 15 years to the day after killing his own big sister. The first film ends with him seemingly shot dead, but then mysteriously vanishing; the sequel, set later that same night, sees him to come back to get final girl Laurie (Jamie Lee Curtis) in the hospital.
The Twist: it turns out Michael wasn't just out to kill random teenagers that Halloween night: he was specifically targeting Laurie, because - although she didn't know it - she is actually his little sister!
Why It Doesn't Work: Admittedly there's a lot about Michael Myers we need to take with a pinch of salt: how does he know it's Halloween, know how to find his home town, or know how to drive a car when he's been catatonic since he was 6?
The fact that he also knows this girl he's never met is his sibling, when almost no one else is aware of this, is a stretch too far. Worse yet, it robs the original of much of its mystery.