WHAT TIME IS it? That’s the question most frequently raised by this slender comedy, yet another featuring male friends refusing to grow up even though they’re in their 30s.

At the outset, Ray (Chris O’Dowd) is sacked from his theme park job because his overacting as a starship trooper scares the children. His buddies (Dean Lennox Kelly and Marc Wooton) are reduced to wearing silly dinosaur costumes to hawk a fast food outlet. They’re not nerds, Ray insists in the pub that evening, but “imagineers”.

Then he meets Cassie (Anna Faris), who claims she came from 150 years in the future to repair a temporal leak. It seems to be in the pub loo. That reference prompts another question, as does a funny sequence involving the three men and a urinal: why British humour is so preoccupied with toilets and what happens inside them.

What encourages us to stay alert is wondering what time it is, and not just because the movie sags in the middle and ennui sets in. This is a tale that shifts by just minutes into the past and by decades into the future, and sometimes features the imagineers watching themselves in scene replays from different angles.

A wry, mildly diverting yarn, it is suffused with movie references and nostalgia for the 1980s. The musical cues for time travel are chart- toppers by Bucks Fizz ( The Land of Make Believe) and Bonnie Tyler ( Total Eclipse of the Heart), and the time portal, when eventually revealed, resembles a disco prop from that era.

Then again, the movie’s scale and ambitions appear limited by budgetary resources and the expense of providing matching hoodies for a few dozen extras at a purportedly futuristic party.

Directed by Gareth Carrivic. Starring Chris O'Dowd, Dean Lennox Kelly, Marc Wootton, Anna Faris 15A cert, Cineworld, Dublin; Carrick Cineplex, Leitrim; Boyle/Carrick Cineplex, Roscommon, 83 min