There doesn’t outwardly appear to be a psychotic killer on the loose in “Jungle,” the sixth feature from slash-happy Aussie horror specialist Greg McLean, but it turns out Mother Nature is more than happy to do the honors. A booby-trapped backpacker survival saga set in deepest Bolivia, based on a memoir by Israeli explorer Yossi Ghinsberg, “Jungle” may ostensibly be a nobler departure from the exuberantly grisly genre fare on which McLean has made his name — but structurally and atmospherically, it has more in common with his smashing 2005 breakout “Wolf Creek” than you might guess. Taut and rattling in setup, before losing its bearings in more ways than one as no end of jungle fever seizes Daniel Radcliffe’s agonized protagonist, this Melbourne festival premiere should enjoy somewhat safer travels on the strength of its name appeal and handsome National Geographic veneer.
Between last year’s disappointing, James Gunn-scripted gorefest “The Belko Experiment” and the mooted resuscitation of “Wolf Creek 3,” McLean has picked an opportune moment to demonstrate his skills outside the bloodiest horror wheelhouse. Job done. His direction of more character-led adventure material is ruggedly polished and accomplished, though the wittier singularities of his filmmaking only emerge at the grosser extremes of its characters’ collective plight: If you need a gut-twisting scene of a leech being dug out of a man’s forehead using only tweezers, McLean’s gladly your man.
Lacking quite the same degree of confidence is Justin Monjo’s script — adapted from Ghinsberg’s 2006 bestseller “Jungle: A Harrowing True Story of Survival” — which alternates between over-efficient short cuts in storytelling and characterization, and messy, unilluminating internal digressions into both clipped backstory and hallucinatory fantasy. The opening frames set up a lyrical, loquacious voiceover for Ghinsberg (a fuzzy-faced Radcliffe, sporting an acceptable Israeli accent), only for the device to be summarily abandoned moments later, once he has declared his restless hunger for escape and earthly discovery.
It’s an appetite that has led him to reject his middle-class parents’ expectations of college education in Tel Aviv. In 1981, not long after completing his naval service, he arrives in Bolivia, intent on following hordes of other dreamy twentysomething travelers through the customary sightseeing excursions and psychotropic night trips. There, he befriends kindly Swiss teacher Marcus (Joel Jackson) and alpha-male American photographer Kevin (Alex Russell) and the three swiftly become a firm unit. Monjo and editor Sean Lahiff waste no time in cementing this core relationship, though a little more time exploring the bonds and fault lines between this trio of psychologically disparate men wouldn’t go amiss; as the film progresses, no one ever fully makes the jump from type to character.
All three men, however, are open books compared to Karl (Thomas Kretschmann), a surly, enigmatic, evidently seasoned German trail-leader who offers Ghinsberg an off-piste trek to spectacular Inca sites in a vast, uncharted stretch of jungle. His approach is more menacing than inviting — true story or not, audiences could be forgiven for wondering if he’s a Teutonic cousin to “Wolf Creek’s” outdoorsy megavillain Mick Taylor — but Ghinsberg is swayed, as eventually are his more skeptical cohorts. Into the unmapped undergrowth they go, heedless to most reasonably viewers’ “don’t do it” cries, whereupon things quickly unravel, their gung-ho spirit barely lasting past the first campfire.
Shades of a more tropical “Deliverance” ensue as physical and emotional strain separates the men into factions, aggravated by a bout of perilous river-rafting, with the withering Karl a team unto himself throughout. His cloudy motivations remain the nerviest source of tension in “Jungle” — though whether he’s brutish, malevolent or simply out of his depth, he’s not the most immediate threat in the wilderness. The film’s second half, which subdivides the group by circumstance until Ghinsberg is wholly isolated, plays as a veritable “Fear Factor” parade of jaguars, snakes and assorted crawling nightmare fuel: Land and water alike prove impossible to master as the diminished explorer seeks sanctuary.
While McLean keeps things lively with a handful of elemental jump scares, the narrative in this section turns as unmoored and mud-logged as its protagonist, with a series of increasingly gaudy dream sequences, delusions and stray domestic flashbacks only superficially admitting viewers to his addled psyche. In a performance that, by the end, isn’t far from merging into his recent “Swiss Army Man” turn, Radcliffe suffers with credible agony and dignity, though it’s Australian up-and-comer Russell who finds the most interesting grooves in his underwritten role, playing up both the cocky entitlement and, gradually, the stubborn integrity of a jockish archetype.
Technical contributions are robust across the board, with Johnny Klimek’s score blending conventional and more indigenous acoustic instrumentation to rather spry effect, resisting the doomier sonic cliches one might expect. And if the characters’ expedition still seems patently ill-advised, Stefan Duscio’s sweeping, verdant widescreen lensing ensures we’re as drunkenly sold on the landscape — not Bolivia, as it happens, but a convincing combination of Colombia and Queensland — as they are.