Slumdog Millionaire (Danny Boyle)
Role Models (David Wain)
Sex Drive (Sean Anders)
Defiance (Edward Zick)
Hannah Takes the Stairs (Joe Swanberg)

Watching Slumdog Millionaire is like being run over by a carnival. It is a colourful way to go, if you don’t mind being cut short in your prime. But you cannot help thinking that back then – in your prime (an hour or a minute ago) – you were enjoying plain life and reality, while there is none of either in Danny Boyle’s feelgood Mumbai tale. It explodes like a street festival, from the early scenes of scampering poverty and tragedy, filmed like demented out-takes from City of God, to the 20m rupee climax on an Indian television version of Who Wants to Be a Millionaire?, whose previous questions, pinning the hero Jamal (Dev Patel) to his spotlit dreamtime, have been spaced through this multiple-flashback movie to structure and punctuate it.

Visually Boyle is on Trainspotting form, full of heady inventiveness. He deserved a script that matched his stylishness. But screenwriter Simon Full Monty Beaufoy, adapting Vikas Swarup’s novel Q & A, has springcleaned it of credibility and substituted what could charitably be called a fairy tale. The point about a fairy tale, though, is that it has one far-fetched premise – the ignition key to its story – after which everything purrs logically from point to point. Here every scene is a wild whimsy, lashing the viewer on through wonder, joy, tears and every other strenuous, ersatz caprice in its weather system.

Each moment makes its point like a party piece, then passes on. The spirit of aspiration bursting up through poverty? That will be the scene of the pre-teen Jamal (Ayush Mahesh Khedekar, pictured above) staggering forth from a latrine-dunking to hustle a passing Bollywood superstar for his autograph. Love? That would be Latika, Jamal’s childhood girlfriend, who grows up through three different performers until reaching the flower of womanly beauty (Freida Pinto). Ruthless Mumbai corruption? That would be the snarling pimp who enslaves her and also the cops who, startlingly, drag Jamal away from Millionaire’s first recording session and torture – yes, torture – him to determine if he was cheating.

Don’t worry about suspending disbelief: for an hour or so Boyle will do it for you. The film’s visual panache is strong enough to ambush doubters, whose scepticism will stumble into hidden nets and be hoisted high into the firmament. You cannot not marvel at the bravura of early scenes, shot by cinematographer Anthony Dod Mantle (of The Last King of Scotland and the Danish Dogma masterworks) with furnace colours and thrilling camera movements. You cannot not warm to the child actors who make merry with their chance at fame, even while the movie’s trauma tourism turns a city’s social tragedy into a series of lollipop adventures.

Maybe only a critic will develop cynical fatigue at all, as the optimism marches on. But for me the game was up with, first, the assumption of the teenage Jamal’s role by Dev Patel – a dolefully inexpressive young actor also handicapped by strikingly dissimilar features to the previous Jamals – and, second, with the rush-to-resolution of every subplot as time runs out and the audience threatens to turn back into a pumpkin. A post-Halloween pumpkin. For after sitting there for so long in a grinning glow of acquiescence, each facial response sliced into shape by clever cine-sculptors, the time will surely come when every thinking viewer decides he is being taken for an overgrown melon.

The week’s two best films are from Hollywood. Role Models and Sex Drive are low comedies of high invention, raunchy rite-of-passage larks that show how good popular US cinema can be when it shares out candour like comical candy.

We were all young once, so in Role Models we empathise with the two thirtyish slackers condemned to community service (Seann William Scott, Paul Rudd) after an energy-juice bender and also with the two luckless youngsters entrusted to their mentorship. The wonderful Jane Lynch (40-Year-Old Virgin) steals each of her scenes as the charity project leader, a reformed cokehead singing from the right-on community care hymnsheet. In Sex Drive a swottish hero (Josh Zuckerman) motors to Tennessee to lose his virginity to an internet date, but reckons without capricious Amish car mechanics (Seth Green), roadkill possums who won’t lie down and an older brother with skeletons in his homophobic closet. Neither film wins a prize for visual style. Each deserves one for clever gags and zanily zig-zagging dialogue.

Tales of true-life heroism need a sense of true life. Otherwise they are just Boy’s Own yarns with bragging rights – “believe it, it happened”. Why should we believe it? And what exactly happened in the source events inspiring Defiance? Undoubtedly a band of Belarusan peasants did hole up in forests during the second world war, gathering might and mass to defy the Nazis. Undoubtedly, too, if director Edward Zwick (The Last Samurai) has done his homework, they were led by two brothers (played by Daniel Craig, pictured, and Liev Schreiber) who survived to emigrate to the US.

The quibble is in the details. Did these people really spend all their time scrapping like drama queens over food, women and battle tactics? Did they speak in an annoying Slav-accented English? (Surely the rule in cinema should be: if every character is the same nationality, just speak with the language and accents of the actors.) And was their forest a place of arty desaturation, shot by cinematographer Eduardo Serra as if he wanted to do black-and-white or sepia, because that is history, but had to compromise with a half-way palette because that – colour-mania – is Hollywood? A stirring story ends up being lost in a stir of clichés and designer desultoriness.

Joe Swanberg’s Hannah Takes the Stairs, the latest comedy of mannerisms in the “mumblecore” style, is maddening for 60 of its 83 minutes. In mumblecore movies – slices of extemporised realism in which the actors workshop their characters in ad-lib sessions with the director – the central idea must be strong or we are just watching onanistic doodling.

Andrew Bujalski got it right as a filmmaker in Funny Ha-Ha and gets it right here as an actor. Playing a tousled pretty-boy running to fat, the middle victim among three serial boyfriends of the neurotic heroine (Greta Gerwig), he gibbers and jabbers convincingly. Every other actor spends an hour playing cute for the camera, before a goodish late scene between Gerwig and boyfriend number three (Kent Osborne) hits an emotional nerve and finally the film is up and running. Unfortunately there are only 20 minutes left for it to run. The moral for mumblecore? Get your mumbling over earlier and get to the core faster.