Perhaps "The Thirteenth Floor" might seem fresher or more interesting if we hadn't already seen so many other science-fiction thrillers with a similar premise.

Oh, who are we trying to kid? This half-baked cobbling of "The Matrix," "Dark City" and "Dr. Jekyll and Mr. Hyde" — by way of "Chinatown" — wouldn't seem particularly fresh or inspired even if it had been the first of the current sci-fi film crop.

It doesn't help that the movie telegraphs its "surprise" ending by a mile. Suffice it to say that few, if any, audiences will have a hard time figuring out the film's conundrum-within-an-enigma-wrapped-up-in-a-mystery — and only if they're not paying attention.

And to be honest, the real mystery here is why the filmmakers picked two such uncharismatic actors — Craig Bierko and Gretchen Mol — to play the lead characters.

Bierko stars as Douglas Hall, a computer software programmer who's been at work on a new virtual reality program, one that will allow users to fully interact with characters and surroundings from 1930s Los Angeles.

Though Douglas believes the program is still months or years from completion, his partner, Hannon Fuller (Armin Mueller-Stahl), has been using it for his own purposes. Worse, Fuller turns up dead and all the evidence points to Douglas as the killer.

With help from his assistant (Vincent D'Onofrio), Douglas enters the reality simulation as one of its characters but leaves with even more questions. Compounding matters further is the arrival of a beautiful young woman (Mol) who claims to be Fuller's daughter and who may hold the key to the mystery.

That may sound intriguing, but in the hands of director and co-scripter Josef Rusnak it quickly goes downhill. Rusnak doesn't seem to have a firm grasp on the subject matter, which veers wildly between bits swiped from other movies.

He also commits the cinematic crime of not answering many of the questions the film poses, or examining most of the subplots, such as the notion of the characters' dual identities in "reality" and the "simulation." (Let's just say there's a big "huh?" factor at work here.)

And Bierko and Mol are too dull to be interesting, while Mueller-Stahl and D'Onofrio are wasted in underwritten supporting roles.

"The Thirteenth Floor" is rated R for a particularly brutal tussle, gunplay and a stabbing, profanity and brief gore.