Lots of characters in action movies mutter about being "too old for this (bleep)," but film stars don't always do them (or us) the courtesy of actually trying to look or act too old for (bleep) of any kind.

So it's refreshing that Bruce Willis, still a reasonably trim 50, goes to almost Dennis Franz-ian lengths to convince us that his Detective Jack Mosley is as much of a shambling, alcoholic wreck as the screenplay for "16 Blocks" insists that he is.

The persuasive seediness is a nice touch in a middling crime thriller that gets a lot more mileage out of its enjoyable performances than out of anything in its pedestrian plot.

Dragging one leg and shlepping a sizable beer gut, Mosley limps into the precinct house and disinterestedly asks the secretary, "Anything for mefi"

"Breath mints," she says firmly, before ticking off the reports awaiting his attention.

The most important item on Mosley's agenda is a mindless errand to escort a jailed witness to a court proceeding. No fuss, no muss, no movie.

I mean, of course there's a movie, so, yeah, the fuss and muss kicks in when gun-toting goons attempt to put a bullet in the brain of sweet, simple Eddie Bunker (Mos Def) while Mosley is making a pit stop for Schlitz and Advil.

Eddie, as fate would have it, is due to blow the whistle on some dirty cops, including Mosley's sneering ex-partner (a nicely sinister David Morse) -- but only if he makes it to the courthouse alive by 10 a.m. Guess who'd like to keep that from happeningfi

The movie benefits greatly from having a little grime under its nails. Director Richard Donner takes an effectively gritty, street-level approach to the setting and characters, and Willis does just fine as a crusty, perpetually hung-over loser determined to "do a good thing."

There's also the very charismatic Mos Def, who uses a nasal whine for almost all of Eddie's dialogue and isn't afraid to come across as a bit of a twerp. The same character in almost any other movie would be a thug or dope dealer, so it's intriguing that Eddie's just a kid who wants to open a bakery.

Despite the ticking clock, Donner doesn't impart much urgency, frequently halting the action for lengthy speeches and stalling it out altogether with an interminable standoff involving a New York City transit bus.

Writer Richard Wenk's bag of tricks is so shallow that he uses the same cliché -- a gunman has the drop on a defenseless victim, but after we hear a shot, it's the killer who keels over, felled by an off-camera shooter -- twice in the film's first 20 minutes.

And after writing himself into a corner, he dials up the oldest trick in the book, having one character be goaded into an absurd confession of all his crimes by another character who's secretly taping the whole conversation. Gotcha!

The bad guy falls for that one every time. It's the people in the theater who always see it coming.

This story appeared in The Daily Herald on page A1.