It is easy to imagine why Another Earth took this year's Sundance Festival by storm. It was written by its attractive blonde star and its storyline includes several things Sundance audiences like: an alienated protagonist, a family-shattering car crash and an atmosphere of gloom.

If that were not enough, it combines its standard-issue plot with an artificial science-fiction conceit about a parallel earth suddenly appearing in the sky, and providing a giant metaphor for second chances.

Writer Brit Marling plays Rhoda, a high-school student who has just won a place to study astrophysics at MIT on the evening that the planet appears. Driving drunk after a party, she smashes into another car, killing a child, his pregnant mother and putting the driver, a music professor, into a coma.

Four years later, Rhoda is out of prison and racked by guilt. She decides to make a confession to the composer (William Mapother) who is now a hermit-like wreck living in a filthy house surrounded by bottles of booze. But, once there, she loses her nerve and claims to be part of a cleaning service.

Soon she is regularly cleaning his house and helping him to feel normal again. It is only a matter of time before the development of one of those Monster's Ball relationships, in which someone falls in love with a person who has, unbeknown to them, done them great harm.

Meanwhile, Rhoda has applied for a seat on a rocket being sent to the other Earth, inhabited by our doubles. She vaguely thinks there may be redemptive value in meeting her other self.

The sci-fi aspect of the plot feels tacked on and is lazily thought-through, though director Mike Cahill has the special-effects skills to make the other Earth look gorgeous and real.

Otherwise Another Earth ticks every irritating hipster box of low-budget "indie" filmmaking. Dialogue is mumbled and the default emotional register is inarticulate glumness. There are sudden zooms, jump-cuts and poorly lit scenes. And the two main characters wear the woolly hats that are de rigueur in "mumblecore" hipster indies.

Yet Rhoda's despair feels real, as does her misguided attempt to redeem herself. Shame the filmmakers felt the need to "deepen" the story with a half-baked cosmic subplot.