Apparently scripted by an especially depthless range of greetings cards, this big screen effort from the creator of This Is Us dishes out tragedy to Oscar Isaac, Olivia Wilde, Annette Bening - and its audience

Dan Fogelman is the weepie whisperer, the man who brought the tearstained TV drama back into vogue with his sentimental – and massively successful – series This Is Us. Here he tries out the same recipe on the mid-level blockbuster, and delivers the first turkey of the autumn, a flashy but fraudulent treatise on love, loss and – yup – life itself.

Somehow managing to be both manipulative and muddled, it is a film that has already prompted critics to utter the dreaded ‘c’ word – in comparing it to Collateral Beauty. While I’m not sure it’s quite at that level of end-of-days infamy, it certainly does possess the same cynical Clinton Cards mawkishness, though one undercut with a strange glib brutality towards its characters. Terminal illness, suicide, repressed childhood trauma, molestation, multiple fatal vehicular accidents: if a terrible fate exists, someone here has already been befelled by it.

Over a series of four interweaving chapters and an epilogue, we follow a phalanx of individuals who are connected in surprising – and frankly convoluted – ways. First up on the chopping block is Oscar Isaac’s Will, a man who has been driven to drink, drugs and Annette Bening’s therapist by a messy separation from his partner Abby (Olivia Wilde). Through tricksy flashbacks we learn about how the pair met, fell in love, and acquired a dog named Fuckface (one of several jarring moments where Fogelman seems to revelling in the freedom not afforded to him on primetime TV).

When Abby falls pregnant it seems to put a tidy bow on her and Will’s enduring love, but then suddenly she leaves him. Or does she? Fogelman here decides to introduce the conceit of the unreliable narrator. It’s a theme that supposedly hangs over the entire film – “Life itself is the ultimate unreliable narrator”, we’re told on several occasions – though really its only real use is to facilitate a great whopping twist involving Will and Abby’s relationship.

For all its contrivances, it should be said that this is probably the strongest portion of the film, offering up a smattering of decent zippy one liners, many of them from Mandy Patinkin and Jean Smart as Will’s parents, and a solid stint by Isaac in the lovelorn sadsack role. Things quickly tumble downhill from here though as we’re whisked forwards in time to meet Will and Abby’s daughter Dylan, a tortured young punk – or at least a mainstream approximation of what a punk might behave like. From there we head, bewilderingly, to Spain, where Fogelman drops the narrative trickery to tell a stodgy Telenovela-lite tale of lowly olive farmer Javier (Sergio Peris-Mencheta), Bella, the woman he loves (Laia Costa) and the landowner (Antonio Banderas) seeking to steal her from him. (Or is he? etc etc).

Facebook Twitter Pinterest ‘Through tricksy flashbacks we learn about how the pair met, fell in love, and acquired a dog named Fuckface’ Photograph: Allstar/AMAZON STUDIOS

On and on it goes, characters and contrivances piling up, before an epilogue belatedly attempts to knit everything into a vaguely comprehensible whole. You rarely get the sense of Fogelman’s characters being complex figures with internal lives – instead they’re merely there to smile weakly through whatever trauma their sadistic creator puts them through.

Ahead of Life Itself’s premiere Fogelman, perhaps anticipating the rollicking the film was likely to receive, wrote an op-ed for Deadline where he defended sentiment as a cinematic tool. “I made this film so people could walk out of a movie theater feeling better than they did when they walked in”, he wrote. And he’s right: when used properly sentiment is a powerful and underrated tool in a film-maker’s arsenal. The problem comes when the viewer can see the film-maker cynically doing everything in his power to make them blub. It’s fine for Life Itself to be soppy, but it’s unforgivable for it to be so sloppy.

• Life Itself has premiered at the Toronto film festival and is released in the US on 21 September and in the UK in January