This is a time travel movie that's not the least about time travel. All the usual conceits, paradoxes and rules of time travel are brushed aside in the brief exposition sequence where Tim's Dad (Nighy) explains to Tim (Gleeson) that the men in the family have the ability to go back in time.

The butterfly effect, betting big on games you know the outcome of to strike it rich, stopping someone being born – they're all explained as being impossible, inconvenient or silly dreams that won't work out and as Tim says in his voiceover, he knows from the day his Dad lays it all out (his 21st birthday) that for him, it'll be all about love.

Surprisingly, given the premise and all the marketing about it being a boy meets girl story, he gets the girl fairly quickly. After an aborted attempt with the hottie who comes to stay at the family's sprawling country house, Tim goes to London to pursue a career as a lawyer. He meets the girl, American expat Mary (McAdams), a cutely twee girl he comes across in an unusual blind date and falls for as soon as he sees her for real.

From there the stakes are all pretty low, so it's a surprise the movies keeps hold of you as much as it does. There's never any real threat to Tim's relationship with Mary as they get married and have a daughter and life moves on as it should. When the dark turn comes, it's with his crazy sister Kit Kat (Wilson) who's carefree lifestyle and bastard boyfriend has landed her in trouble.

The climax involves a rite of passage in Tim's life that's inevitable no matter how sad, and the only aspect of it that time travel can change is that it gives Tim a chance at a decent goodbye.

All in all it's sweet and cute, and the instances where Tim does invoke his strange power feel in hindsight like they should have had more consequence in his life. But maybe I'm just too used to Back to the Future, The Terminator and the other sci-fi trappings of time travel.