8 Mile

A trashy mouth? Me? But I'm a noble prince...

I'm tempted to resort to the old film review cliché and say that the real star of Eminem's debut feature is the city of Detroit. Director Curtis Hanson made his name as a screen urbanologist with LA Confidential, mapping the underside of noir-era Tinseltown, and the underrated Wonder Boys, which put Pittsburgh's grey suburbs to wistful use. If there's much to remember in 8 Mile, it's the austerely uninviting scenery, a blasted remnant of once-mighty industry. Shot by Amores Perros cinematographer Rodrigo Prieto, Hanson's most striking sequence is a slow crawl, viewed through a bus window, past a succession of dead buildings and wastegrounds, one big burned-out nowhere (the stretch of Detroit road referred to in the title.)

It would have been a really interesting challenge for Hanson to give us two hours of empty street scenes – no plot, no characters. For not much else in 8 Mile really seems to inspire him, least of all its star. Written by Scott Silver, this is effectively a biopic-à-clef, a thinly-disguised retelling of Marshall Mathers' early struggles as a novice rapper, in the lean times before he blossomed into America's first convincingly controversial pop star in years. To Hanson and Silver's credit, the film doesn't remotely come across as an ad for Eminem the Product, yet it lacks the energy that might have pushed it in a compelling direction of its own. 8 Mile feels like an extended screen test – a noncommittal experiment to gauge the boy's celluloid presence. Given his earnest moodiness, I can see him passing muster in a thriller as a tough but vulnerable maverick sidekick to a hard-boiled older cop. It would be more convincing than the sullenly wounded James Dean persona he tries on here.

Eminem's character Jimmy Smith Jr, aka Bunny Rabbit, is a white kid in a predominantly black community, trying to prove himself as a rapper. We first see him taking part in a live rhyming contest but suffering a silencing attack of stagefright, itself such a novel sight that the film could have been advertised on this point alone, along the lines of "Garbo Laughs" – "America's premier motormouth clams up".

But Jimmy will overcome – rap is his only way up from the bottom. He has a soul-destroying job on a steel press, has split up with his girlfriend, and is reduced to moving back in with his mother Stephanie (Kim Basinger) in her dingy trailer. After reviving Basinger's career as a sleek vamp in LA Confidential, Hanson gives her the chance to get down and dirty again, but grittiness doesn't necessarily add up to a substantial character. It's clear Stephanie is an excruciating liability to Jimmy: she's first seen when he walks in on her naked and straddling her boyfriend, a sight from which the tender youth recoils with a wince of unexpected delicacy (what, you thought he'd yell, "Yo Mom, nice butt!"?). But there's no real heart in the portrayal of this bad mother straight from the dysfunctional-trash cookie mould: we're invited from the start to disapprove of her uncontrolled indignity. For dignity, and tenderness, are what Jimmy, for all his piqued outbursts, represents: he's the only one who really cares for his moppet of a kid sister.

Sulky but noble, he's a true prince, which is presumably why his crew of buddies – three black, one white – so loyally support him. Future (Mekhi Phifer), who hosts the rap contests, seems to have infinite faith in his genius. Even though Jimmy dries up on stage, there's little doubt that he is – to use a loaded phrase from boxing history – rap's Great White Hope.

In fact, the film makes heavy weather out of Eminem himself being the white rap champion who pushed an African-American art form decisively into the MTV mainstream. The script recognises the contradictions of this, with Jimmy's black rivals calling him "Elvis". But it's remarkable how often Jimmy is seen struggling against black oppressors – the gang members who give him a surprisingly desultory beating, the foreman at work, the parasitic false friend.

Jimmy's crew, meanwhile, are sympathetic but barely sketched out – one charismatic dandy, one fat guy, one politico who's depicted as a harmless amiable windbag, and a nervous white dork. But everyone's moral worth is measured solely in terms of their support for Jimmy's aspirations. His new girlfriend – Brittany Murphy teetering on precarious heels and prodigiously slutty, like a kindergarten Courtney Love – is unreliable, but still turns up to stare in awe at him on stage. Besides, she's pursuing her own dream of being a model, and the film respects her will to do whatever it takes: it's a traditional American tale of individualism seeing it through.

Not that you quite believe in Jimmy's burning spirit: the film so downplays Eminem's trademark cartoon brattishness that he barely registers as a combat-hardened punk, let alone a streetcorner satirist. He's more a compassionate loner, a hip-hop Holden Caulfield. When his crew burn down an abandoned house that's become a danger to local kids, he's the one who ruefully picks up a photo of the black family who once lived there: somehow, he alone represents the pained conscience of the community. Still more excruciating is the moment when, in an impromptu lunch-break rap session, he breaks in on a co-worker with the line, "OK folks, enough of the gay jokes" – a rather coy irony from a star who's made comedy homophobia a hot ticket.

If the film wants to show rap as a lifeline to sanity in a deprived world, it ought to make the most out of celebrating verbal invention; instead, the presentation actually undermines it, reduces wordplay to another tough pose. A cluttered sound mix means you can rarely make out the words. The on-stage rapping is pretty much obscured by crowd noise and general atmospherics: we get the rhythms of Eminem's whiny staccato, but little of his actual verbal cut-and-thrust.

While most of the drama barrels monotonously from confrontation to confrontation, the big rap contests themselves, disappointingly, are less the promised gladiatorial combat, more like rather formal taunt sessions, each contestant insulting the other in alternating 45-second bursts. The concluding showdown is so anticlimactic it could be a sixth-form debating final: "This House Believes Your Mama's A Ho." Jimmy neatly pre-empts attack – "I am white, I am a fuckin' bum, I do live in a trailer with my mom" – then exposes the reigning champ's privileged background and, incredibly, leaves him speechless. Effectively, he silences his opponent by proving that he himself is more real, more oppressed – which, in this setting, is tantamount to claiming he's more authentically black.

Despite this uncomfortable subtext, the film doesn't manage to be all that provocative, or dynamic. After the witty Wonder Boys, Hanson seems to have run out of gas on a sometimes ludicrous, mostly just drab exercise in recycled Skid Row heroics: the film ends with Jimmy striding back to his nightshift down a desolate alley, which is as close as an inner-city boy gets to riding off into the sunset. 8 Mile may successfully strip away the tawdry glamour and paper-thin gangster mythology routinely attendant on rap cinema, but this covertly sentimental scrapyard realism doesn't make for any more compelling drama. 8 Mile finally does little justice to its star's singularly confrontational talent. Jimmy may get called "Elvis", but if Eminem's abrasiveness gets diluted much further on screen, we may yet see his Blue Hawaii.

j.romney@independent.co.uk