Zooey Deschanel is best known for her gigantic blue eyes, which are wide and lovely and invite the viewer to dive right in.

And perhaps break a clavicle, because I'm not sure how much depth there actually is.

Deschanel's off-kilter line readings and spaced-out persona make her a natural for certain kinds of comedy, but she's a bit of a cipher, and I've yet to see her in a role that reveals a substantial core.

Ditto "500 days of Summer," featuring Deschanel as a girl named Summer, as warm and beautiful and fleeting as the name suggests.

Tom (Joseph Gordon-Levitt) is smitten with Summer, and he's so high on infatuation he doesn't notice the relationship is one-sided and headed for, well, a Fall.

No, I'm not giving anything away. The filmmakers devise a time-fractured narrative that numbers and rearranges the days of their courtship, so that one of the first things we see is their breakup and its aftermath (a vignette that might have been called "She's Just Not That Into You").

So the rest of "500 Days" sets up as a bit of a mystery, and we look for clues, even as their romance is fresh, for the hairline fractures that might eventually result in a compete break.

They're not easy to spot. Gordon-Levitt and Deschanel have nice chemistry, and their meet-cute, date-cute scenes have real energy - as when so-and-so gets poop-faced at a karaoke bar and embarrasses himself with a Pixies song.

"500 Days" has a bit of a weakness for kooky music, and there are other elements here that push it toward the ranks of the dreaded Quirky-Funny Indie. Chief among them: a sarcastic, worldly tween who's wise beyond her years. Because she's SCRIPTED.

Then there is the matter of Deschanel, who's fascinating to Tom but opaque to us. Though, to be fair, Tom's crush-distorted view of things is part of the point.

As for Gordon-Levitt, he's been heralded as some kind of new Brando, though I think he's about as big as Brando's left leg.

And he'll never be taken Brando-serious until he gets that mop of hair off his forehead.