As modern, red-blooded men and women, we all know what it feels like to wake up in a strange restroom with one foot chained to the plumbing and no recollection of the past day's events.

Can I get an amen?

The makers of “Saw,” an intriguing but ultimately unfulfilling life-or-limb thriller, take this novel premise to radically perverse extremes.

Regaining consciousness, Dr. Lawrence Gordon (Cary Elwes) finds himself surrounded by items both ominous and inexplicable. A hacksaw. A corpse. A micro-cassette tape recorder. And, most significantly, a fellow captive named Adam (Leigh Whannell) who similarly has no idea how or why someone would bind him in shackles on the floor of a derelict restroom.

Until the first flashback mutilates the illusion, “Saw” — the brainchild of Whannel and fellow Aussie film school prodigy James Wan — has a surreal, one-act urgency that recalls “Waiting for Godot” highlighted with the murky death-fetishism of “Seven.”

Confused and angry, the men cycle through the expected emotions (disbelief, suspicion, uneasy camaraderie) while analyzing the clues (a freshly mounted wall clock, to name one) that might explain their situation. Elwes (“The Princess Bride”) is too pillowy and self-amused as Lawrence, but Whannell shows real promise as Adam, a sass-talking slacker with a secret.

The more convoluted the plot becomes — and the more satellite bit roles the filmmakers throw into orbit (Danny Glover plays a cop, Monica Potter the doc’s wife) — the less imprinted we feel to the plight of the characters. A hidden audio tape reveals the truth: Lawrence and Adam are at the mercy of the Jigsaw Killer, a notorious psychopath who reminds his victims how precious life is by making them perform horribly ironic (and often deadly) tasks. To wit: Lawrence, a man of healing, is instructed to free himself and kill Adam or face an even more unthinkable fate.

This psycho-killer-as-life-coach stuff is hard enough to swallow without all the hopscotching that goes on after director Wan’s tight, theatrical opening act. Using the most tenuous of connections, the filmmakers essentially launch into an omniscient flashback that allows us to bear witness to all of the killer’s past stunts, including jaw-ripping headgear and an obstacle course made of razor wire.

Grisly, yes, but also fitting — that a movie strewn with severed limbs should itself feel so dramatically disjointed.