10 Most Confusing Movie Endings People Don't Understand

4. Primer

The entirety of Shane Carruth's cult sci-fi gem Primer is an exercise in having your brain slowly melted, let alone its headache-inducing ending.

Carruth, a former engineer, refused to dumb down any of the film's technical dialogue, the result of which is a film heavy on jargon and therefore extremely tough to unravel, especially on a first viewing.

The film revolves around two engineers, Aaron (Carruth) and Abe (David Sullivan), who accidentally create a crude time machine of sorts, and before long all hell starts to break loose.

Aaron and Abe initially use time travel to make profits on the stock market, but their conflicting philosophies - Aaron keen to exploit time travel, Abe deeming it too dangerous - inevitably leads them down a dark path involving numerous competing timelines and realities.

Though it ultimately appears that the two manage to resolve the anomalies, the ending reveals the full extent of Aaron's ambition, with numerous temporal versions of himself in play as he goes ahead with building a warehouse-sized time machine.

This is a massively simplified explanation of the film's plot - which is literally too dense for words - and in many ways its labyrinthine nature is very much the point. But there's no shame in being confused by it, or as the case may be, considering it too heady for its own good.