Will the real Slim Shady please stand up? If you go to see 8 Mile thinking it’s a literal reworking of Marshall Mathers III’s life, well, that’s probably a whole other movie. But if the rapper’s film debut uncannily resembles his own rise to fame, it’s no accident. Producer Brian Glazer had been shopping this script even before Eminem barrelled up the charts with his white-boy-outta-the-ghetto shtick, but Glazer knew he’d hit box-office gold by casting the guy who was living out the tale.

We know the story—poor kid grows up rough on the mean streets of Detroit, finding refuge in the rap music that eventually gets him out of the ’hood and into the spotlight. If only director Curtis Hanson (L.A. Confidential) had let the natural power of the underdog’s rise dictate the pace of the film. Instead, we get the rather plodding tale of Jimmy, a.k.a. “Rabbit” (Eminem), an aspiring rapper who’s mad at his life, his town, and most everyone else. He channels his frustration into his lyrics, but despite prepping for weeks, chokes in his first rap “battle.” “You win battles, you get respect,” someone says, and that’s about as far as character motivation goes here.

Rabbit lives with his druggie mom (a completely miscast Kim Basinger) and adorable kid sister in the trailer park while spending his days in drudgery at the sheet metal factory. Only his rap and his friends, including best pal David “Future” Porter (a solid Mekhi Phifer) pull Rabbit through the days along the “8 Mile” (the cracked roadway dividing Detroit’s burned-out downtown from the wealthier suburbs).

But writer Scott Silver only takes baby steps toward the rags-to-riches archetype you’d expect. Instead of Rabbit rising up out of the ghetto on his sheer talent, all he gets is a couple weak battles and a recording contract. 8 Mile has been compared to Rocky, but there’s not enough real fight here to sustain the parallel.

Hanson and cinematographer Rodrigo Prieto (Amores Perros) capture the look and feel of mid-nineties Detroit in bleak greys and blacks, with a handheld-camera feel in several scenes. While the rap battles aren’t quite as visceral as one would hope, given that the premise of the film rests on the role of hip-hop as saviour, there is a gritty realism to them and the Detroit-centric soundtrack that pounds away beneath the visuals.

But the real question is, can Eminem act? The role of Rabbit isn’t much of a stretch, right down to the hooded sweatshirt and sullen expression, but there has always been something magnetic about the rapper. That he’s able to carry the movie practically by himself is impressive, and he displays a vulnerable side usually hidden beneath his aggressive rap persona. Eminem already has the rare distinction of having a movie and an album top the charts simultaneously—if he can parlay his unique energy into a completely different role in a future film, he may just be unstoppable.