By JASON LLOREN
Blast Film Critic

Porter, the character Mel Gibson portrays in his latest action flick "Payback," must have some serious hemorrhoids. For sure, he's got a huge grudge ­ he, his wife and a fellow crook just stole some loot off some Chinese money launderers and now those two just shot Porter in the back and left him for maggot food. He's pissed. Seriously pissed. Doesn't-crack-one-damn-smile pissed.

But he's still good ol' Mel, right? This is the same wisecrack who charmed audiences in "Lethal Weapon" playing an edgy cop. Here, however, Gibson plays this one straight. Porter is mean and brutal. So's the film. So if you can't handle watching some heads get knocked, pass this film.

The film begins with Porter getting a few bulletholes plugged up by a back-alley surgeon. Blood cakes his scarred and bruised face. Soon, Porter is out on the streets, recovered and on the trail of his betrayers. He tracks down his wife Lynn (Deborah Kara Unger), a junkie who's wasting away in her home. He next comes in contact with a lowly mob, made of a bad-dressing guy named Stegman (David Paymer) and two crooked cops.

They provide his means to finding the crook who stole his share of loot off him ­ Val (Gregg Henry), a bleached blond thief with a taste for sadism. Val used the stolen loot, including Porter's share, to pay off a debt to an organized crime outfit strangely referred to throughout the film as the Syndicate. And now Val is a made man in this mob.

To find out the Syndicate's HQ, the same hotel where Val's bedding up in, Porter enlists the help of the one character he apparently trusts ­ his ex-girlfriend Rosie (Maria Bello). She's a former whore who used to be in the employ of the Syndicate. Porter confronts Val and bangs him up a bit to get him to cough up the money. The beating helps but the money transfer has to be postponed until Val can make a withdrawal.

Soon, other groups move in on Porter and his soon-to-be-delivered loot. Stegman's crew threaten Porter with their badges unless they can get their cut (one of the cops wants to buy a houseboat). Then comes the Asian hoods who were robbed by Val and Porter to begin with. Complicating it further, the Syndicate becomes intrigued by Porter. They figure, hey, if this guy has the brass to kick the crap out of Val, one of their own members, what's to stop him from breathing down the Syndicate's neck? Now Porter has a new headache: a contract out for his life.

And all he wants his is money.

The plot moves forward with a series of violent episodes: Porter is shot in the back twice. He pulls a dope dealer's nose ring off the hard way. Val gets punched in the torso and groin (first by an S&M hooker) and kicked in the head. Thugs take a hammer to Porter's toes. A lot of blood is spilled and many bones are crushed. None of it pleasant or for humorous effect.

Along the way, Porter waste the thugs who keep getting in the way of his movie, each time coming in contact with a more senior member of the Syndicate. An ongoing gag is them questioning the $130,000 he purports to claim, and Porter reminding them it's a mere $70,000.

"Payback" is one of those films where you'll flinch and grimace in empathy as bones are cracked and heads are kicked. It's hard to recall a mainstream film that was so directly brutal in its portrayal in a while. But that shouldn't come as no surprise since "Payback" was directed by screenwriter Brian Helgeland, who demonstrated an adeptness at depicting straightforward violence in his adapted screenplay of the superb "L.A. Confidential."

Helgeland colors the film with a cold blue hue that renders what would normally be a bright sunny day into a gloomy overcast one. Sets of concrete warehouses and dilapidated apartments look like the color of corpses in a morgue. These characters are scum and the camera makes them appear devoid of souls. Overall he does a decent job depicting this fairly straightforward tale of money and revenge.

The problems are with the film's mood and tone, which seems mixed at best or, at worst, uncertain. As Val takes Porter's boot to his face, Dean Martin's "Ain't That a Kick in the Head" plays in the background. Instead of imbuing "Payback" with a sense of irony, that song merely comes across as whimsy. The movie wants to be playful at times when it seems like it could go the exact other way: brutal and direct. Some minor plot tie-ups are clever. Porter comes up with a nice way to get back at the crooked cops without resorting to bloodshed. But even that provides little narrative payoff. It shows Porter using his head. Great. Next victim, please.

Much has been reported about Helgeland's resigning from the film after Gibson insisted on changes (A screenwriter and an anonymous director were brought in to make script changes). It's harder to judge Helgeland's overall contribution to the film when we don't know for sure what aren't his scenes in the film. This is for sure: The last 15 minutes of the film have a lighter, breezier feel to it, a subtle change from the hardened tone that dominates the story. The ending feels too conventional but overall the payoff from "Payback" is a decent return on our box-office investment.

Grade: C+