Sylvester Stallone insisted he would only do another ''Rambo'' flick if it was about the human condition. He stuck to his guns. Chapter 4, simply titled ''Rambo,'' is about the condition of humans - after they've been blown apart by bombs, land mines and projectiles fired from the biggest, loudest firearms you may ever encounter on screen.

A box-office and critical joke for years with a string of absurd movies, Stallone regained a lot of good will with fans on 2006's ''Rocky Balboa,'' a resurrection of his most-famous character that proved an unlikely commercial success and also earned the respect of many reviewers. ''Rocky Balboa'' got back to the core of the lovable goof known as the Italian Stallion, evoking a lot of the charm of the original ''Rocky'' and rinsing out some of the bad taste left by the increasingly caricatured sequels.

Co-written and directed by Stallone, ''Rambo'' is sickening, almost degenerate, in its savagery. Any hope that it might redeem the franchise the way ''Rocky Balboa'' did vanishes about the time a Burmese soldier bayonets the belly of a child during one of the movie's early sequences of utter carnage. ''First Blood,'' which introduced Stallone's Vietnam vet John Rambo, was silly in its relentless one-man-army action. But that 1982 flick at least brushed up against relevant questions about how a nation welcomes back the killing machines it creates to do its dirty work without figuring out some way to flip the off switch.

There never has been much story to the ''Rambo'' movies, whose last installment came in 1988. The latest ''Rambo'' has a thin setup - Stallone's stoic soldier living out his life as a boatman and snake-catcher in Thailand when he's approached by American missionaries (Julie Benz and Paul Schulze among them) to ferry the group upriver to help villagers endangered by civil war in Myanmar (formerly Burma). Rambo reluctantly agrees, then later finds himself joining a team of mercenaries hired by the congregation back home to find out what happened to the missionaries after the village they'd been working in is exterminated by the army.

He didn't ask for it, he didn't want it (and neither did we), but Rambo once again becomes an up-stoppable demon of death as he tears through the jungle slaughtering bad guys with bow and arrow, his bare hands in one particularly bloody moment, and a gun that could bring down a T-Rex. The body count is phenomenal, and Stallone's effects team at least deserves credit for the twisted skill with which they create new and gruesome ways to show bodies being atomized amid the explosions and gunfire.

It's a true one-note performance for Stallone, whose Rambo is chided by one of the mercenaries for his ''thousand-yard stare.'' But that thousand-yard stare is all Stallone musters as he mumbles his way through such fortune-cookie justifications for wholesale violence as ''When you're pushed, killing's as easy as breathing'' and ''Live for nothing or die for something.''

At least the movie is short, and in the few quiet moments, sparks of personality emerge from Matthew Marsden, Graham McTavish, singer Jake La Botz and others playing the mercenaries who hitch their wagon to Rambo. The movie might satisfy bloodthirsty action fans, but for most people, this is one Stallone do-over we could have done without.

By DAVID GERMAIN AP Movie Writer

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