12 Best Sci-Fi Movies You Can Watch Online For FREE

Though we're maybe stretching the definition of "sci-fi" a little bit here, Christopher Smith's high-concept Brit psycho-slasher (shot in Australia) takes its intriguing central concept and mashes it together with some delightfully goopy slasher goodness.

Put-upon housewife Jess (Melissa George) takes an impromptu boat holiday with her friends to try and unwind, only to wind up stranded on a seemingly-deserted ocean liner when their boat capsizes in a storm. Not all as it seems though, and the group are menaced by a burlap-sack wearing assailant with murderous intent, an assailant who turns out to be none other than another Jess. And she's not the only one either, there's a whole room of dead doppelgangers.

With its nonlinear narrative centering on a time loop and multiple doppelgangers running around at once, Triangle wears its influences on its sleeve (Memento, Primer, and Back to the Future Part II come to mind), but Smith manages to create a unique and intriguing little horror film that'll leave your own brain spinning in circles like the characters.

George's lead performance as a woman dealing with the constant stresses of dealing with an autistic child seem to foreshadow Jennifer Kent's own acclaimed Aussie psycho-horror The Babadook, and seeing her interact with her multiple doppelgangers as she's slowly forced to do the unimaginable to protect herself and get back home is very compelling. Aside from some questionable American accents from the supporting actors (including a young Liam Hemsworth), this is a very strong and very imaginitive sci-fi horror worth a watch.