Dir: Peyton Reed. US. 2006. 107mins.

Poor star chemistry and a screenplay without a first act - and not much of a final one, either - turn this highly anticipated romantic comedy starring Vince Vaughn and Jennifer Aniston into a keen disappointment.

But the film has so far proved critic-proof. Thanks to a strong marketing push from Universal Pictures and considerable interest in whether the two leads have as much on-screen chemistry as they have off-screen, opened with an estimated $38.1m for a strong average of $12,395, considerably more than had been expected at the start of the weekend. It's also rated PG-13 so might attract parents with kids.

But worldwide, where Vaughn's 2005 smash comedy The Wedding Crashers made just more than 25% of its $285m gross, prospects seem questionable. Break-Up rolls out internationally between June 8 and Sept. 22.

Alas, word will get out fast that the interaction in this Peyton Reed-helmed high-concept film lacks the sexy sparks that off-screen couple Brad Pitt (Aniston's ex) and Angelina Jolie brought to last year's hit Mr and Mrs Smith. Those tickled by Vaughn's The Wedding Crashers also may be disappointed. Here, although he has his funny moments and amusing wisecracks when blithely conversing with deadpan pal Jon Favreau, his character comes off as a bickering, clueless jerk in front of Aniston. And his tender scenes with her fall flat.

That leaves as the primary audience those who loved Aniston so much on TV's Friends they'll see her in anything. But as last year's Rumor Has It showed, that's not inherently a big crowd. As for growing her audience with Break-Up, she's simply too inexpressive an actress and her face too ordinary to be a galvanizing screen presence. And when forced to go deep with her anger, as in a crucial kitchen confrontation with Vaughn early in the film, it's just not there.

The movie's plotline concerns the emotional ups and downs of a couple trying to break up even though they still love each other. But it fails to establish why the twosome ever came together. In the opening scenes, Vaughn's Gary - a blue-collar Chicago ethnic type - spots Aniston's preppy Brooke at a Cubs game and irritatingly flirts by plying her with unwanted hot dogs.

Over the subsequent opening credits, a montage of still photographs unconvincingly argues that was the start of a whirlwind romance rather than grounds for a harassment arrest. But once the story starts in earnest, they're in their condo fighting over huge cultural differences. From what is shown of their outside lives - he works at a declasse family tour-guide business; she at an upscale contemporary art gallery - it makes sense for them to separate as soon as possible. Makes sense to everyone, that is, but the film-makers.

What the film would like to be is a sophisticated yet zany, bittersweet yet funny, look at the hard work of finding and keeping love. Like Wedding, it uses lots of pop music and tries to make its supporting characters strikingly eccentric, including the delightful John Michael Higgins plays Brooke's brother who loves to break into song.

But overall the screenplay shows evidence of belabored rewriting in an unsuccessful attempt to come up with the right balance of humor and melodrama. Vaughn shares a "story" credit with newcomers Jeremy Garelick and Jay Lavender, but didn't help much. Director Reed, who also bombed with the awkward Down With Love, has no feel for place other than some occasional establishing shots of the Windy City. And he lets actors get away with clashing tones. Judy Davis' diva-style take on a sexually forthright, aging gallery owner is downright grotesque while Vincent D'Onofrio's ranting as Gary's brother is weirder than his role in Men in Black.

Cinematographer Eric Alan Edwards mostly just points and shoots at whoever is talking, although at one moment the camera turns inappropriately jittery. Editors Dan Lebental and David Rosenbloom deserve the most credit for ruthlessly cutting so as not to prolong all the dead-end vignettes that never cohere into a satisfying story.

Screenplay
Jeremy Garelick & Jay Lavender

Story
Vince Vaughn & Garelick & Lavender

Production company
Mosaic Media Group (US)
Universal Pictures (US)

Worldwide distribution
Universal Pictures
United International Pictures in Argentina, Switzerland, France, Netherlands, Singapore
Solar Films in Philippines

Producers
Scott Stuber
Vince Vaughn

Co-producers
Jeremy Garelick
Jay Lavender

Executive producers
Stuart M Besser
Peter Billingsley

Cinematographer
Eric Alan Edwards

Editors
Dan Lebental
David Rosenbloom

Music
Gunnar Madsen

Main cast
Jennifer Aniston
Vince Vaughn
Judy Davis
Jon Favreau
Vincent D'Onofrio
Joey Lauren Adams
John Michael Higgins