20 Most Rewatchable Sci-Fi Movies Of The 21st Century

20. Primer

Shane Carruth’s mind-bending 2004 debut borrows heavily from the enigmatic director’s background in advanced mathematics and engineering for its convoluted tale of two graduate students who uncover the secret to time travel.

Now there’s no denying that this one will require more than one viewing solely so the befuddled viewer can understand its complex structure and interweaving time loops, but the flick rewards patience with a logical puzzle more complicated than most mainstream sci fi feels comfortable messing with.

Carruth’s follow-up Upstream Color may be more emotionally engaging, but for sheer mental legwork, few films can beat the notepad-requiring depths of Primer’s knotty timeline.