Before watching the movie:
Exploring parallel outcomes of a small change in one’s life is hardly a unique source of plot, especially since Many Worlds Theory entered popular consciousness. Malcolm in the Middle did an episode on what would happen depending on which parent chaperoned an outing, one of Community‘s most popular episodes traces seven different continuities, Mister Nobody follows a mind-bending number of possibilities, and Constellations recently began a Broadway engagement, just to name a few, and completely ignoring the countless examples involving time travel. However, there are two films that are always held up as the chief examples of the concept: the German film Run Lola Run, and Sliding Doors, both of which, interestingly, released in the same year. Perhaps that’s a part of why they both resonate so strongly.
I encountered Run Lola Run first, so I’ve always seen this as the English-language derivative. I expect it to be less experimental in technique and so more accessible, but that’s dangerously close to snobbishness. This is still an experiment in stepping outside traditional linear story, and highly regarded as such, for reasons I’ll now get to experience.