The Times critic A. O. Scott reviews “Spy.”  In “Spy,” a wild, profane, surprisingly bloody caper-comedy, Melissa McCarthy appears on screen with various sidekicks, nemeses, foils, straight men (and women) and human punching bags. Among them are Jason Statham, Jude Law, Allison Janney, Bobby Cannavale and Rose Byrne, who are accomplished and by now fairly well-established banterers and counterpunchers in their own right. Even better — and less familiar — are Peter Serafinowicz and the marvelous Miranda Hart (Chummy to all you “Call the Midwife” fans out there) as two of the unlikelier C.I.A. employees in recent cinema.  But this movie, written and directed by Paul Feig, is very much Ms. McCarthy’s show, a potential franchise built around her talents and her proven audience appeal. When “The Heat” (also directed by Mr. Feig) was released a few years ago, I complained that its threadbare genre elements made it a less-than-perfect vehicle for its newly fledged star. That film’s box-office mileage suggests that I may have been wrong, and even though “Spy” is similarly engineered to be easy, forgettable fun, it is likely to be a big hit.  And why not? The busy, silly script allows Ms. McCarthy to be her own best sidekick, in effect an entire sketch-comedy troupe unto herself. She starts out as Susan Cooper, a mousy, cheerful desk jockey at C.I.A. headquarters where, despite her training and her status as a full-fledged officer, she is ignored and belittled. Her job is to be the eyes and ears of Bradley Fine (Mr. Law), a glamorous would-be 007 who relies on Susan’s expertise and toys with her feelings.  A preview of the film.  Susan is anxious, awkward and eager to please, her intelligence and competence in perpetual struggle with her low self-esteem. Once in the field, though, she undergoes a transformation that is all the more entertaining because it doesn’t quite make sense. Rebelling against the typecasting of her undercover identities — a Midwestern cat enthusiast, a bedraggled single mom — Susan reinvents herself as an elegant espionage artiste. Instructed to observe and report on the doings of a Bulgarian arms dealer (Ms. Byrne), she goes rogue in every imaginable way and proves herself adept at fighting second-string femmes fatales and random dark-suited minions, as well as flying planes and conducting high-speed chases through European cities.  Melissa McCarthy and Miranda Hart in a scene from the film.  Along the way she tangles with Mr. Statham’s character, an arrogant peacock who brags about exploits that sound like outtakes from Jason Statham movies. She also attracts the attention of Aldo (Mr. Serafinowicz), an amorous Italian who shows up every time “Spy” threatens to tilt too far toward the action end of the action-comedy spectrum.  This movie is fancier than “The Heat” or “Bridesmaids” — flush with high-end visual effects purchased on the strength of their success. And the big, hectic set pieces aren’t bad, as long as the gunfire doesn’t drown out Ms. McCarthy’s floridly inventive insults and non sequiturs. There’s an undercurrent of cheeky surrealism that sometimes pops to the surface: For some reason C.I.A. headquarters are infested with bats and mice; for some reason the rapper 50 Cent is in Budapest; for some reason Ms. Byrne is Bulgarian.  Even better is the blithe feminism that makes “Spy” feel at once revolutionary and like no big deal. It’s not just that the movie aces the Bechdel test. It didn’t even need to study. The movie isn’t uplifting; it’s buoyant. While Susan at first clearly has a lot to prove — that she’s a skilled professional and a ruthless adversary, everyone else’s doubts to the contrary — Mr. Feig doesn’t make her proving it the central arc of the narrative. Instead, he highlights Ms. McCarthy’s quickness and unpredictability, her genius for defying logic and decorum. She can be ridiculous and heroic, needy and scary, clueless and clever — in quick succession and sometimes all at once.  “Spy” is rated R (Under 17 requires accompanying parent or adult guardian). Salty and bloody.  Written and directed by Paul Feig; director of photography, Robert Yeoman; edited by Brent White and Melissa Bretherton; production design by Jefferson Sage; costumes by Christine Bieselin Clark; produced by Mr. Feig, Peter Chernin, Jenno Topping and Jessie Henderson; released by 20th Century Fox. Running time: 1 hour 59 minutes.  WITH: Melissa McCarthy (Susan Cooper), Jude Law (Bradley Fine), Jason Statham (Rick Ford), Rose Byrne (Rayna Boyanov), Miranda Hart (Nancy), Bobby Cannavale (Sergio de Luca), Allison Janney (Elaine Crocker) and Peter Serafinowicz (Aldo).  A version of this review appears in print on June 5, 2015, on page C1 of the New York edition with the headline: A Triple Threat to Foreign Femmes Fatales. Order Reprints| Today's Paper|Subscribe
Ms. McCarthy leads a starry cast in this action-comedy about an intelligence officer who proves her mettle in heroic and ridiculous ways.