The Bigger Picture: Now, here's a forward-thinking villain: Saw mastermind Jigsaw (Tobin Bell) was offed at the end of Saw III (the new film opens with his ridiculously graphic autopsy), but he's still killing people right and left. This time around, he's going after more of the cops tasked with stopping his reign of terror—which seems a little petulant, since it's not like they've been doing a great job of it.
Death hasn't done much to mellow Jigsaw. The requisite elaborate deathtraps (pneumatic eye-gouger! human kebab-er!) of Saw IV have less of a set-piece feel—a welcome relief from the heavy-handed metal-video vibe of Saw III—but they're nastier than ever, and his grand plan is apparently grinding closer to fruition.
Not that you have any way of knowing. The only thing more tortured than Jigsaw's victims is the labyrinthine, kaleidoscopic plot, which staggers drunkenly along the slenderest of tightropes. To have any comprehension of what's going on you must simultaneously (a) remember what happened in the earlier films and (b) willfully forget the contradictory elements of said films, all the while watching multiple story threads that may or may not be connected or sequential.
And then there's the twist at the end, a franchise trademark that really ought to have expired by now, along with the irksome tradition of rewriting the last film while making the next one. The series has essentially become a shell game, entertaining for a while if you can stomach the gore, and then the credits roll and you're pretty sure you've been cheated somehow.
The 180—a Second Opinion: Look, by the time the fourth film in a franchise rolls around, the audience is pretty well-defined. Apparently the audience for Saw films likes nihilistic characters, bone-cracking death traps, fountains of blood and insanely self-referential plotting. If that's not you, rent something gentler. Like The Texas Chainsaw Massacre or, oh, Triumph of the Will.