Jigsaw is dead, to begin with. There is no doubt whatsoever about that. Old Jigsaw is as dead as a doornail. But if you thought that meant the end of the Saw pictures, then you obviously didn't come of age in the era of A Nightmare on Elm Street and Friday the 13th. With four hugely successful installments already on the books and a fifth one almost certainly set to hit theatres next Halloween, Saw is the 21st-century version of those long-running franchises, which have racked up a combined 17 films (18 if you count Freddy vs. Jason) over the past two decades. And while the prospect of a Saw 18 seems unlikely, there's no reason why we shouldn't expect to see Saw 8 or even Saw 10 before the series finally calls it a day, especially now that the producers have overcome their biggest hurdle, namely the death of the central serial killer, John Kramer a.k.a. Jigsaw.

As you may recall, Saw III ended with Jigsaw's throat being sliced open by a contestant who had survived one of his elaborate games. Saw IV opens with the feared killer’s lifeless body being dissected in graphic, gruesome detail on a morgue slab. (In case you were wondering how returning director Darren Lynn Bousman would top the extended brain surgery sequence seen in the last movie, here he gleefully shows the coroners cutting through Kramer’s skull and lifting out his brain before peeling back his rib cage and removing his organs. Even for a desensitized gore fan like myself, this scene tested the ol’ gag reflex.) During the operation, an audiotape is discovered in Kramer’s stomach that indicates that Jigsaw’s games will continue from beyond the grave. This time around, his target is SWAT officer Rigg (Lyriq Bent), who has spent the past two movies watching his colleagues fall prey to Kramer’s schemes.

The rules of his game, as always, are simple—Rigg has 90 minutes to navigate a series of traps and if he succeeds, he’ll find his former partner, the long-missing Detective Matthews (Saw II’s Donnie Wahlberg), waiting for him. Meanwhile, two FBI agents (Athena Karkanis and Scott Patterson) try to learn more about Kramer—and the person who might be continuing his work—by interrogating his ex-wife Jill (Betsy Russell), who reveals, among other things, that she was once going to give birth to Jigsaw Jr., until tragedy claimed the unborn baby and set John on his path to becoming his deadly alter ego.

Although Saw is on course to match A Nightmare on Elm Street and Friday the 13th in terms of longevity, there are some striking differences between the franchises. For one thing, the Nightmare and Friday sequels were largely standalone affairs where the only constant was Freddy or Jason slaughtering a bunch of nubile teens. The Saw movies, in contrast, are fanatical about continuity. Even though new characters are introduced in each installment, the filmmakers go out of their way to establish exactly how they fit into the larger Saw mythology. Likewise, faces previously glimpsed in bit parts are subsequently revealed to be major players. One of the key figures in Saw IV, for example, is a heretofore-unseen character named Art (Justin Louis), who turns out to have been Kramer’s one-time business partner. And then there’s Detective Hoffman (Costas Mandylor), who appeared fleetingly in Saw III but by the end of this installment proves that he’ll be a crucial part of the franchise’s future.

Saw fans love the series’ attention to detail, but with every new character and plot twist, the overarching story has grown increasingly arbitrary and nonsensical. The absurdity reaches new highs in Saw IV, which asks us to swallow developments that simply aren’t logistically possible, never mind realistic. The last ten minutes are particularly baffling, as they require Jigsaw to be in two places at once, suggesting that he’s either mastered the art of cloning or has a long-lost twin brother who is also conveniently dying of cancer. But then, the majority of moviegoers aren’t returning to Saw again and again for the story—they want to see what new torture devices the filmmakers have dreamed up.

Unfortunately, Saw IV disappoints on that level as well. There’s little imagination in this crop of traps, particularly when compared to the key-behind-the-eye sequence in Saw II or the drowning-in-pig-guts stunt in Saw III. As sad as fans may be to see John Kramer go, maybe a new Jigsaw is exactly what the series needs to stave off franchise fatigue. After all, few things are more irritating than a rusty Saw.