10 best time travel movies ever, ranked

Time travel is so confusing as a concept that most sci-fi movies gloss over the finer details. Primer is on the exact opposite side of the complexity spectrum, layering on scientific jargon that remains untranslated and largely incomprehensible for most viewers. Unraveling its twisty plot is the main appeal of Primer.

Looper toys with the paradoxical implications of time travel without getting bogged down in the mechanics. Instead, it focuses on the mind-bending premise of an aging assassin meeting his younger self — and fighting him to the death.