But if 127 Hours did a masterful job of exploring the psychology of its trapped canyoneer hero, taking us into Aron Ralston's head and heart, Sanctum hardly bothers with such business. The thrill-seekers here are just two-dimensional cutouts in a 3-D tableau: Carl (Ioan Gruffudd), a hotshot American financier who has also scaled Mount Everest; Victoria (Alice Parkinson), his extremely sporty gal-pal; Crazy George (Dan Wylie), the experienced hand; Luko (Cramer Cain), the faithful native; Judes (Allison Cratchley), the dangerously tired and untethered diver; and - the big relationshop - Frank (a buff Richard Roxburgh), arrogant veteran caver and leader of the pack, and Josh (Rhys Wakefield), his 17-year-old son. Their relationship is marked by scowling disapproval (Frank) and defiant shrugs (Josh).
With ace underwater photography and scuba-diving stunt doubles, Sanctum doesn't stint on action. Wild flumes hurl the cave divers against the smooth rock faces of their eerie subterranean aquatic world, while ego clashes and fractious rivalries - not to mention a mounting sense of dread - hurl one diver at the next.
Director Alister Grierson and cinematographer Jules O'Loughlin appear to have studied Cameron's Avatar long and hard, framing their shots with looming foreground figures and artful off-in-the-distance-ringed-in-light silhouettes. Cameron's own underwater epics - The Abyss, Aliens of the Deep - also seem to be of influence. Perhaps Cameron's patented 3-D equipment came with a proviso: Pay homage, or else. And I can swear there's a line of dialogue - "What can possibly go wrong diving in caves?" - that was dubbed by Cameron's Aliens and Avatar muse, Sigourney Weaver.
But that was probably all in my head.
Contact movie critic Steven Rea at 215-854-5629 or firstname.lastname@example.org. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/onmovies/