When the original “Saw” was released in 2004, the movie about a serial killer who offed deserving victims with elaborate Rube Goldberg devices suited to their sins made a considerable splash with its combination of visceral violence, puzzle-minded plotting and a big concluding twist. It aimed low but hit the target, and audiences responded big-time. The 2005 sequel was a lame affair, basically a tale of a passel of people trapped in an old house whose traps they must escape or be killed, sandwiched within a dumb “Saw” wraparound story. Now the writer and director responsible for that sequel (the director of the initial picture, James Wan, is still involved with his collaborator Leigh Whannell on the story side, and among the producers, but has otherwise gone on to other things) have come up with another helping. They should have stopped when they were behind.

“Saw III,” as it’s imaginatively titled, not only takes up where the second installment left off, but offers some info that goes back to the original as well. It also brings closure, you might say, with an ending that seems insured to preclude a further entry featuring the same villains, the horrible Jigsaw (Tobin Bell) and his ex-junkie assistant Amanda (Shawnee Smith). And though there are plenty of the gruesome deaths-by-horrible-device for which the series is notorious, the plot eventually settles on two victims: Lynn (Bahar Soomekh), a doctor in a troubled marriage whom Amanda kidnaps to treat the dying Jigsaw–and dresses in an explosive neck brace to insure her cooperation–and Jeff (Angus Macfayden), a single father obsessed with taking vengeance on the man who killed his young son in a traffic accident but received only a light court sentence. Both are put through the ringer to achieve Jigsaw’s ultimate goal–which, as usual, is steeped in misdirection (as well as, as usual, going way beyond unlikelihood to absolute absurdity).

There’s really no reason for this “Saw”–except, of course, to rake in scads on money, which it will undoubtedly do over this Halloween season. And it seems that the makers felt no great compulsion to rethink their formula to any substantial degree. The problem is, that the formula has gone stale. By now this franchise has spawned entirely too many imitators, and most have taken the Sadism-Is-Us business to a higher level (in quantity, not quality) than “Saw III” can now muster. The torture sequences come across as all too familiar, and comparatively pallid; and the whiplash-edited montages of blood and gore seem old hat. Indeed, the grisliest and most effectively disgusting sequence doesn’t have to do with the deaths at all–it’s the brain surgery on Jigsaw. To make matters worse, as the series has progressed, Bell’s role has increased exponentially; he’s always been a windbag, with reams of dialogue in which he not only gives orders but pontificates endlessly on his perverted ideas of justice, but here his garrulousness reaches new heights–of pomposity on his part and boredom on ours.

No kudos are due to the actors or production team. Macfayden has certainly fallen from the heights of the recent “Pride and Prejudice,” in which he played Darcy; he’s too good for such stuff, but one supposes he needs paychecks, too. Everyone else is strictly mediocre, with Smith worse than that, and the assumed disappearance of her (and Bell) from any further “Saws” will be a blessing. The picture has the same raw, ugly look as its predecessors, which is a either a strength or a weakness, depending on your point of view.

The “Saw” franchise was never particularly sharp, but by this time it’s grown extremely dull in every sense. Even the most devoted fan won’t find much to enjoy in this grab-bag of tired cliches and inept tricks.