Keanu Reeves spends most of Street Kings, the noisiest collision of cop flick cliches since Hot Fuzz, looking like he can't hear himself think.

Normally, this would be a problem, but here Keanu-as-RoboCop's inexpressiveness works surprisingly well -- partly because the movie is ear-bleedingly loud with gunfire, and partly because the filmmakers themselves seem in a daze over what kind of movie they were making.

Is it a hard-boiled portrait of a savage urban underbelly, in which Dirty Harry would be considered a softie? Or a rebuke of police rot and vigilantism?

Reeves' signature blankness lets you, the moviegoer, decide; he's the acting equivalent of an Etch-a-Sketch. As for the answer to the above questions, the movie ultimately reveals itself to be neither. Or maybe both. Like so many thrillers with crooked moral backbones, Street Kings glamourizes the very behaviour it's condemning, lest audiences get bored by too much talk and not enough killing.

When Reeves' LAPD Det. Tom Ludlow, buzzed by vodka and blood-thirst, mows down a house full of Korean thugs in the film's opening moments, it leaves you more adrenalized than repelled.

Sure, the gangsters had forced young girls into sex slavery -- the thugs got what they deserved -- but director David Ayer seems unwilling to let audiences settle in with proto-Hollywood hero-cop mythmaking. Instead he's treading in the same territory as L.A. Confidential and Training Day. No surprise there -- Ayer wrote that Denzel Washington thriller and noted noirist James Ellroy, author of Confidential, is credited with co-penning Kings. But compared to those films -- especially L.A. Confidential -- this is strictly silly, scattershot and second-rate.

Ludlow's world, such as it is, comes crashing down shortly after the raid on the Koreans. For one thing, his former partner Terrence Washington (Terry Crews) may have snitched him out to Internal Affairs. And to make matters worse, Washington quickly winds up gunned down in a grisly grocery-store massacre after which Ludlow becomes the prime suspect. Enter Hugh Laurie, of TV's House, as an IA watchdog.

Forced with having to exonerate himself, Ludlow ventures into the netherworld that scarcely separates police and perps. On one side there is his brotherhood of self-styled justice junkies, led by Forest Whitaker. On the other, there are the career villains who inhabit L.A.'s most unforgiving criminal epicentres. Who's behind what, unfortunately, couldn't be more obvious if the answer walked up and pepper-sprayed you.

For all of the film's flaws -- it pales next to TV's The Shield or The Wire -- Ayer's muscular direction doesn't skimp on energized mayhem. Better bombastic than boring, I guess. Even Whitaker soars off the rails by the screaming-match climax, in which saliva spittle flies as plentifully as bullets.

The other cast members are largely mismanaged in puddle-deep parts and one-dimensional walk-ons, including Laurie who hardly registers above the sound of his own snark.

(This film is rated 18-A)