Trainwreck, film review: On a romcom joyride with outrageous Amy Schumer

"Monogamy is not realistic" is the message drummed into the heroine from earliest childhood in Trainwreck, the uproarious new romantic comedy written by and starring Amy Schumer.

In romcoms, it goes without saying that true (monogamous) love will triumph… eventually. Much of the pleasure of Trainwreck lies in Amy's ferocious resistance to her own inevitable final-reel fate. Schumer is like a latter-day Mae West: glamorous, promiscuous and with a very fatalistic view about men and relationships. She has a devastating turn of phrase, too. Irony and sarcasm are second nature to her.

Films made by and starring stand-up comedians tend to be episodic. They often consist of comic sketches strung together rather than a smoothly hewn storyline. Trainwreck, which has comedians in many of its leading roles, is a jolting and uneven ride but also frequently a hilarious one.

Director Judd Apatow was accused of sexism by one of his own leading actresses after Knocked Up (2007). Trainwreck shares its raunchy humour but, like Bridesmaids (which Apatow produced), it is a female-driven comedy in which the men are frequently the butt of the joke.

The film begins in poignant and very funny fashion. Young kids Amy and her sister Kim listen to their father, Gordon (Colin Quinn), explaining just why he shouldn't be blamed for cheating on his wife and wrecking his marriage. The sequence is shot in sepia tones, as if it is some magical family memory, and Gordon's message to his daughters is that adults are like children. They don't want to play with the same toys all the time. "What if I told you that was the only doll you were allowed to play with the rest of your life? How would you feel?" the father asks. "Sad," the daughters reply. It is just the answer that he wants.

Twenty-three years later, Amy is a successful magazine journalist working for S'Nuff, a lads' mag edited by the formidable Dianna (Tilda Swinton), a blithely ruthless English woman abroad. Although Amy hates sports, she is assigned to write a profile of top sports doctor Aaron Conners (Bill Hader.) Inevitably, she and Aaron begin to fall in love.

Aaron is friend, confidant and medical adviser to real-life basketball star LeBron James. There have been celebrity cameos from sports stars in movies for many years. They generally tend to be excruciating. Bucking this trend, LeBron James turns out to be a skilled comedic actor who isn't embarrassed about sending himself up. One of the world's highest-paid athletes, the basketballer is portrayed here as being comically vain and self-obsessed and more interested in watching Downton Abbey than in playing in the NBA.

For no particular reason, we see clips from a spoof indie art-house romantic drama called The Dog Walker, starring Daniel Radcliffe and Marisa Tomei. It's a bit of an in-joke, an earnest black and white movie with an utterly absurd premise, but is still amusing.

Markedly less funny is another equally self-conscious scene, late on, in which top sports commentators and former stars (including ex-tennis champ Chris Evert) offer their analysis of the relationship between Amy and Aaron. There is a creeping sentimentality in the film's treatment of the daughters' relationship with their ageing but still combative dad.

Trainwreck is very scattergun in its references and jokes. Gags based around vomiting and bad sex are interspersed with scenes that pastiche Woody Allen's Manhattan. Occasionally, the film begins to take itself a little too seriously. The film-makers go out of their way to show Amy's disdain for the cosy bourgeois, married life enjoyed by Kim (Brie Larson) and her wimpish husband Tom (Mike Birbiglia.) At the same time, that is the kind of life she risks being sucked into herself.

As the film progresses and Amy's options narrow, Trainwreck risks turning into a dispritingly conservative and traditional affair. It is the story of the taming of a free-spirited and independent woman. Amy, as first encountered, may drink too much and have a very chaotic love life but she isn't beholden to any man. It is a point of principle that she never spends the night with her boyfriends.

Amy's final surrender to convention is signalled in symbolic fashion in a witty and well-choreographed set piece in which she performs as a cheerleader – but this is a role that previously she would have regarded with utter contempt.

Schumer's screenplay wants to have it both ways: to celebrate Amy's rebelliousness and promiscuity while also eventually turning her into the conventional romcom heroine. Schumer, though, is an utterly engaging screen personality. Whether she is the abrasive cynic of the early part of the film or the Cinderella-type she becomes in the final reel, we can't help rooting for her. She has an everywoman quality. As Swinton's patronising editor tells Amy, she's "clever" but she is not too "brainy", she is "pretty but not "gorgeous". She is "approachable". Everybody likes her. Her comic observations may sometimes be vicious but she makes them in such a friendly way that no one seems too offended.

The very title Trainwreck suggests that Amy's life is a disaster. That, of course, isn't the case at all. "I am just a modern chick who does what she wants," Amy declares. This is far too cheerful and good natured a film to leave any real emotional carnage in its wake. Its contradictions are obvious but its one consistent quality is it humour. Amy sees the comedy in everything from divorce to death and, most absurd of all, her own romantic longings.