How scary is SAW 3D, exactly? Well, let me tell you how it affected me: it was scary enough to elevate my heart rate to 108 beats per minute - an increase of 34 bpm over resting rate. I also experienced rising levels of “arousal” 33% of the time. (That’s arousal as in the “fight or flight” response, and nothing sexual. I don’t like torture porn in that way, and anyone who says I do is lying.)

How come I can give you this unwelcome level of detail about my bodily responses? As part of a promotional junket arranged by the film’s distributors, I watched 8 minutes of the film while hooked up to a variety of monitoring devices provided by a mad science/engineering/art collective called Thrill Laboratory. Electrodes on my fingers measured my galvanic skin response (or to use the technical term, “sweatiness”); more electrodes stuck to my face monitored the muscle groups responsible for expressions of “fright” or “delight”; and still more electrodes, stuck to me unceremoniously as I held up my shirt in the foyer of a Staines cinema, measured my heart rate.

Let’s skip the telemetry for a moment and consider my unscientific, subjective response to the clip. The footage I saw continued the fine SAW traditions of sadistic predicaments and increasingly complex elaboration of the earlier films’ backstory. It opened with a character from the first SAW film. We see Dr Gordon (Carey Elwes), crawling away newly monopedal, apparently direct from the original film’s third act, and then cauterising his (unconvincing) stump on a hot pipe. Exciting for SAW continuity nuts who wondered whether he had survived.

The next scene we were shown was one of Jigsaw’s signature “games”. Maybe as a concession to the dimming effect of 3D glasses, it takes place in bright daylight, in a shop window before a crowd of onlookers, rather than the usual dingy warehouse. A woman and two men who are rivals for her affection wake up hooked up to a bondage-and-bandsaws contraption, designed so that each man has to force a saw into his rival to prevent the woman being cut in two.

The 3D - real 3D filmed with twin cameras, rather than the inferior kind added in post-production - works well in this scene, giving a real sense of solidity to the infernal device. There’s tastefully restrained use of eyeball-prodding “things flying at the camera” shots - just a couple of first-person views of the approaching bandsaws, and some blood splatter as things inevitably go badly for one of the victims.

It’s a good set-up, and the reaction of the crowd, who make a half-hearted attempt to break through the window but mainly seem interested in filming proceedings on their mobile phones, might be a sly comment on the voyeurism of the SAW film audience.

I don’t want to spoil who gets cut, but I’ll say that my companion - let’s call her subject D2 - registered no expressions of delight or fright at all. The Thrill Laboratory team were afraid that she might be a sociopath, but her explanation was that she was neither frightened or delighted, just saddened by the misogyny of the scene’s conclusion.

But if you’re a fan of the SAW franchise untroubled by those kind of considerations, rest assured that the decision to make the final installment in 3D is artistically justified and not a meaningless gimmick. If you’re a more casual gore fan, you might want to revise the backstory of the preceeding six films on Wikipedia before you see it. If you’re a real SAW completist, you should also be aware that there are two SAW-themed rides at Thorpe Park, and they made my heart rate go to 198 bpm as I expressed fright 28% of the time. I also squealed like a little girl on a pony farm.

SAW 3D is out in cinemas across the UK now.
More information about the SAW rides at Thorpe Park can be found at www.thorpepark.com

-Ben Henley 2010