Life can get pretty desperate when your mother's dead, your father's a mystery and you're stuck living in your grandparents' laundry room in Jamaica, Queens, without a cent to your name. That explains the title of Get Rich or Die Tryin', 50 Cent's contribution to the dubious new genre, the ''semiautobiopic,'' in which rap stars (such as Eminem in 8 Mile) play loosely fictionalized versions of themselves on film. Funny how these movies never end with the main characters signing multimillion-dollar film deals, but instead wrap long before their street heroes have the chance to sell out.

As unnecessary as these movies seem, especially when you consider how well the audience already knows the rap stars' stories, I suppose there's a certain poignancy to their existence. After all, rap music is, among other things, an outlet for talented songwriters to overcome the adversity they've faced by retelling events in rhythm and rhyme. Why not give them the chance to tell it once again in yet another format?

Now, why such a story would attract six-time Oscar-nominated director Jim Sheridan is another question altogether. Sheridan has long been a champion of the underdog, telling mostly-true stories in which the handicapped (My Left Foot), oppressed Irishmen (In the Name of the Father) and destitute immigrants (In America) wage tirelessly against either The Man or ''the man upstairs.'' Life isn't just unfair in Sheridan's movies, it's rigged against the righteous from the start.

But Marcus (50 Cent's on-screen alter ego) isn't a holy innocent the way Sheridan's other characters are. With the exception of one standout scene in which Marcus' near-death experience is intercut with flashbacks to his fireworks-filled birth, you'd never suspect this was Sheridan's work if the on-screen credit weren't there to announce it.

The movie doesn't glorify Marcus' gangsta lifestyle so much as empathize with the circumstances that motivate it, although it's the Scarface-style displays of illicit wealth and misplaced machismo that are likely to appeal most to audiences. The redemption part of the story suffers by comparison. Unlike this summer's compulsively watchable Hustle & Flow, Get Rich or Die Tryin' captures none of the thrill of finding your voice, recording a demo or landing a concert.

For those who don't take 50 Cent's talent for granted going in, there's nothing to indicate what's so special about him, much less why he of all people deserves to have a movie made about his experiences. In the case of 8 Mile, we instantly understood the uphill battle facing a blue-collar white rapper struggling to be taken seriously, but the hook isn't clear here. Meanwhile, guess who's gettin' richer with every ticket sold.

[as featured in The Miami Herald]