What's great about horror flicks like Scream is that, while not being truly original, they take what's been done before and transform it into a refreshing package, infusing new life into the slasher subgenre. Now, about a decade later, it becomes increasingly clear that Saw may very well have the same impact. It wasn't just another serial killer movie, it had a brain, combining a diabolical mindset with some good old blood and gore to form a movie that didn't just play with the mind. It bounced it off the ground and had you gasping for more. But the trouble with crafting a genre effort that breaks the mold is the inevitable downside that follows: doing it again. Following up Saw seems like making a sequel to The Sixth Sense; the endings of both movies left viewers breathless and wowed. The thought of either one becoming a series with the original shock value intact seems the most inconceivable idea ever. The makers of Saw II have seen this coming, and this sequel is every bit as gruesome and inventive as its predecessor. Most follow-up entries that rush into production in order to tap into a potential franchise come out disappointing, but Saw II delivers the goods.

It continues the story of Jigsaw (Tobin Bell), a sort of serial killer who puts people he believes don't value their lives enough in predicaments where they have to push themselves a little harder than they’d normally be willing to, into retaining the privilege of being alive -- mostly, though, only to die horribly anyway, courtesy of Jigsaw's booby traps. After the police comes upon Jigsaw's latest victim, detective Eric Mathews (Donnie Wahlberg) uncovers the location of the madman's lair and leads the charge to bring him to justice. There's only one problem: Jigsaw already set his latest plans in motion, involving eight people trapped in a house, one of whom is Eric's son (Erik Knudsen). While the detective and Jigsaw play mind games with each other, those stuck in the house, including former Jigsaw victim Amanda (Shawnee Smith) and hothead Xavier (Franky G), search frantically for a way out before the nerve gas flowing through the vents turns their bodies to mash in a matter of hours.

After a year with just a few acceptable horror movies released, it’s good to see Saw II avoiding the bad end of the spectrum. It fuels itself with the same grisly atmosphere and creative energy that made the original movie a modern classic. Both rise above the usual slasher restrictions by not simply killing off characters for the sake of giving the special effects guy something to do. These movies explore the killer's motives, showing how the victims' personalities come into play and the fiendishly clever ways they bring about their own ends, rendering the killer blameless for his crimes (although that's admittedly a thin technicality from a legal perspective). Saw II simply continues the work of its predecessor, taking the story and its various elements to another level while at the same time offering the same smarts, thrills, and diabolical intelligence that made it all work in the first place.

Saw II features more polished acting than the original, however, with a tight shooting schedule, one can't really blame Saw's performances for being a little flat. All the characters serve a narrative purpose for the entire movie, but they each manage to keep the viewer involved in their personal storylines. Wahlberg is your basic grizzled movie cop, swearing with every breath, and Bell is the meek but wily villain. Together, these two develop their own intriguing relationship, one reminiscent of Clarisse and Hannibal in Silence of the Lambs. Less successful are the eight screaming victims who whine about how much they want to get out to one degree or another -- although the filmmakers did a good job of working back in Smith's character Amanda from the first film. Luckily, scenes featuring the deadly traps, ranging from a nail mask to a syringe pit, generate just as much interest and are equally as tense as those in Saw. First-time director Darren Lynn Bousman, who co-wrote the movie with originator Leigh Wannell, not only keeps this inventive streak flowing while weaving a story around it that's consistently suspenseful but, also ends the film with an inevitable plot twist that upholds Saw’s jaw-dropping tradition -- which however is sadly disgraced with an unwarranted montage. But its strengths are its shocks and claustrophobia, realized with stylishly murky visuals and cinematographer David A. Armstrong is back on board here, providing visual continuity.

Whannell and Bousman attempt to prove the age-old hypothesis posed by classic literature like 'Lord of the Flies': with life at stake and hope gone, human beings will revert to their darker, more selfish instincts to survive. The problem with their attempt to tackle such a lofty philosophical precept is that their 'social experiment' needs a little more balance. The trapped characters in Saw II are mostly ex-convicts of one sort or another: junkies, pushers, kidnapers, possibly even murderers. It's not that large of a stretch to imagine that they'd turn on one another. This flaw in the base premise of their argument taints certain stretches of the film -- betrayal is never surprising, nor is it particularly interesting. Perhaps Whannell and Bousman would have done better to include 'normal' or 'wholesome' people. A fall from the lofts of civilization is always more exciting when there's farther down to go.

With that said, and while little time is given to get to know the victims before they're shot, sliced or burned to death, the carnage inside the grubby, strip-lighted prison is strikingly and viscerally staged. What's absent is the original's chilling simplicity, most notably in the muddled finale that makes a mockery of much that has gone before. But still, Saw II is hard to shake off. It works brilliantly, both as a sequel and as a stand-alone creep fest. Additional material by Nate Yapp.