Another Earth, Mike Cahill, 92 mins (12A) A Very Harold & Kumar 3D Christmas, Todd Strauss-Schulson, 90 mins (18)

Science fiction gets the subtle treatment – but then again we are in another world

You wait years for one intimate drama in which an uncharted planet spins towards our own...and then along come Melancholia and Another Earth within months of each other.

That's bad timing for Another Earth. After Lars von Trier's operatic tragicomedy, it was inevitable that any small-scale indie movie with similar themes would seem like, well, a small-scale indie movie. Still, when a film deals with something as big as another world, its modest proportions can be part of its charm.

Another Earth is co-written and produced by its star, Brit Marling. She plays a 17-year-old astronomy enthusiast who celebrates getting into a top American university by getting drunk at a party, only to crash her car on the way home, killing a mother and son. Four years on, once she's out of prison, she visits the widower (William Mapother) to apologise, but loses her nerve and bluffs her way into a job as his cleaner instead. Her diligence and gentleness – and her willowy beauty – start to pull him out of his depression and into a relationship with her. The twist is that on the very night she crashed her car, a new planet was first spotted in the sky, a planet identical to ours in every way.

Even after Melancholia, it's appealingly novel to see such a grand science-fiction conceit treated so matter-of-factly, with no presidential addresses or alien attack fleets. Indeed, long stretches pass without the so-called "Earth 2" being mentioned at all. Marling and Mike Cahill, the film's co-writer-director-producer-cinematographer-editor, use the other world as just one element of their graceful, introspective fable. They're definitely talents to watch.

By the end, though, Another Earth feels as if it hasn't fulfilled its potential. Marling and Mapother's romance is handled with delicacy, but it's far less intriguing than the questions of what you would do if you met your doppelgänger, and how differently your life might have turned out on another planet – questions which keep being raised in tantalising snippets of voice-over, but which are never integrated into the plot. The film's most spine-tingling scene comes when Marling sees a scientist on television making radio contact with Earth 2. A few more scenes like that and maybe Lars von Trier would have had something to worry about.

A Very Harold & Kumar 3D Christmas is a cockle-warming comedy – quite an achievement given that it contains, to quote the parental guidelines, "strong crude and sexual content, graphic nudity, pervasive language, drug use and some violence". The third Harold & Kumar film again stars John Cho and Kal Penn as stoner buddies on a mission. This time they blunder around Manhattan in search of the perfect Christmas tree, upsetting Ukrainian mobsters, inadvertently letting a toddler sample Class A drugs, and hallucinating themselves into a Claymation nightmare.

The relentless taboo-busting is never exactly hilarious, but it's done with such exuberance that even the gags about paedophile priests generate a rosy glow. It's a feeling that's bolstered by the 3D technology, too often simply a way of bumping up ticket prices, but these film-makers take infectious delight in throwing the most inappropriate substances at the viewer, starting with eggs and marijuana smoke, and finishing with something much worse. The film is disarmingly sincere in its filthiness, and beneath it all there's a tender-hearted story of friendship and responsibility. Harold and Kumar are almost as fond of each other as they are of getting high.

Next Week:

Nicholas Barber referees a battle of the colons with Sherlock Holmes: Game of Shadows and Mission Impossible: Ghost Protocol

Also Showing: 11/12/2011

Puss in Boots (90 mins, U)

This mercifully Mike Myers-free Shrek spin-off features a swashbuckling cat (right), voiced by Antonio Banderas, who goes off on an adventure with Humpty Dumpty (Zach Galifianakis), his childhood friend, and Kitty Softpaws (Salma Hayek), his feline love interest. As you might expect from DreamWorks, the 3D animation is flawless, but although Puss in Boots has arch jokes and acrobatic action sequences, grown-up viewers won't find it terribly riveting. There's not much at stake in the nonsensical story. And without getting too veterinary about it, the character of Puss has been neutered.

New Year's Eve (118 mins, 12A)

Garry Marshall's calculating follow-up to last year's ensemble rom-com Valentine's Day all unfolds in New York on 31 December. Katherine Heigl, Hilary Swank, Ashton Kutcher, Jessica Biel and lots of other "stars" you could happily live without turn up in various overlapping non-stories, all of which teach them about love and forgiveness in the most vapid, sentimental way possible. The audience, meanwhile, learns considerably more about the huge corporate logos which appear in sharp focus during every other scene.