Though the film is out more to dropkick your mind than provoke thought, Saw II does contain intriguing talk of absolution amid the crushed heads, blown-out brains and coughed-up innards.

So in that interest, here’s a free pass to the half-hearted Saw for providing a basis for what seems like the gruesome morality play co-writer Leigh Whannell really wanted to make. (Whannell co-wrote and co-starred in the original and cameos here … well, sort of.)

The original was life support for a last-second, gotcha twist that crumbled under 10 seconds of rational thought. Although the Jigsaw killer still has an inexplicably large supply of super-strong sedatives for this sequel, it’s but a small crinkle in an otherwise perfectly creased plot.

Of course, another narrative whammy drops in the final seconds, but the difference is that Saw II doesn’t go through the motions leading up to it. Whannel, who co-wrote with director Darren Lynn Bousman, has great fun subverting cinematic clichés of police interrogation, villain patterns and how we expect onscreen action and justice.

Mentioning Saw II in the same sentence as A History of Violence is slightly sacrilegious, but it’s a case of some similar ideas with, pardon the pun, a way-different execution.

Saw II gets right to the bloody stuff in its opening sequence, which involves a Venus flytrap-style “death mask” and a key embedded in the mask wearer’s flesh. His attempt at self-preservation doesn’t quite work out, nor does Bousman’s ploy to establish tension with ADD editing. But give the movie about 15 minutes, and you’ll realize he’s not totally trying to music-video it to death.

To that opening casualty’s crime scene comes Detective Eric Matthews (Donnie Wahlberg), a divorced cop with an insolent teenage son Daniel (Erik Knudsen) and a super-crummy apartment. The murder fits the pattern of Jigsaw, who creates elaborate, but escapable, deathtraps for his victims — most, but not all, of whom are societal bottom feeders whose efforts to live end badly.

Saw viewers already know Jigsaw’s identity; he’s an evil genius with terminal cancer played by Tobin Bell. Bell is a character actor known largely for lackey roles, and his soft-spoken, almost polite and helpful, demeanor fits the character, and his quasi-peaceable M.O. well. Jigsaw’s still got a screw loose, but he definitely is a straight shooter.

Eric gets involved in a mental cat-and-mouse game with Jigsaw, who kidnapped Daniel just to get started. He’s also infected him with nerve gas, placed him in a house with one burly, violent drug dealer (Franky G) and other felons and given everyone two hours to find antidotes or die. And that’s before they find the syringes, guns and spiked baseball bats.

Not only is Saw II able to largely dispense with red herrings, its focus is less on the killing hardware and more on Jigsaw experimenting with the human capacity for violence and mercy. A few too many people are piled into the narrative, but it adds to the real-time immediacy and the actors, though nothing special, are fine. Anything will do after the original’s Screamin’ Cary Elwes. Saw II’s greatest flaw is the unnecessary, thorny inclusion of two disquieting suicide plotlines.

Still, this is the vehicle for gore and a little bit of psychological torture that the first one started as before getting buried under an avalanche of stupidity. How fitting that, at least most of the time, Jigsaw is all about offering up a second chance.