If you thought Mel Gibson was mean in the "Lethal Weapon" movies, you're in for a real surprise in "Payback."

In fact, Gibson's character is so unrepentantly cruel in this dark comic thriller that many of his fans may be turned off. (The film is based on the Richard Stark novel "The Hunter," which also served as the inspiration for the 1967 film "Point Blank.")

And that's a shame, since Gibson has a lot more fun with this role than anything he's played in a long, long time.

To be sure, the film has its share of problems, including the aforementioned vicious streak (including some troubling violence against women). And there are plot holes so big you could drive a stretch limo through them.

But "Payback" makes up for its faults with nearly non-stop action and some amusing tongue-in-cheek humor.

Gibson stars as Porter, a petty thief looking for vengeance after being double-crossed over a heist and left for dead. First on his list are his former partner, Val (Gregg Henry), and Porter's drug-addicted wife (Deborah Kara Unger), the person who shot him in the back.

However, if he wants to get the money from the heist, he's going to have to go through more than just those two.

Others in his path are Val's mob bosses (William Devane, Kris Kristofferson and James Coburn), Val's sadistic mistress (Lucy Liu, from TV's "Ally McBeal"), her Asian gang friends and a pair of corrupt cops who also want the cash.

Unfortunately, Porter doesn't have any allies, except for Rosie (Maria Bello, from TV's "ER"), a prostitute with whom he shares a past. Needless to say, the odds are stacked against him.

Co-scripter/director Brian Helgeland (who wrote the 1996 hit"L.A. Confidential") doesn't pull any punches here. And the action is excessively violent. Although, for once the material seems to justify it.

Besides, Helgeland smartly brings a lurid, '70s-type atmosphere to the movie (including a vintage soundtrack). Shades of Quentin Tarantino's "Jackie Brown."

It works much better here, as does the casting-against-type of Gibson. (It's hard to say whether he's better served by the sarcastic one-liners or the even-more-sarcastic, monotone voice-over.)

And James Coburn nearly steals the show with his brief performance.

"Payback" is rated R for gunplay, fisticuffs and vehicular violence, profanity, gore, two scenes of excruciating torture, nude artwork and some partial female nudity (Liu's extremely skimpy outfits), sadistic sex acts, drug use and use of racial slurs and crude slang.