"As Above, So Below" is a relentlessly stressful horror flick in the model of a classic haunted house B-movie, with a twist. A ragtag group of explorers, led by an obsessive young archaeologist named Scarlett (Perdita Weeks), is spelunking into the recesses of the catacombs beneath Paris, searching for a magical doodad. The further down they get, the more obvious it becomes that they're descending into hell itself. This begets predicament. Shot by cameras carried and worn by the players — they're making a documentary, so the found-footage gimmick so popular in schlocky, low-budget horror movies at least makes some sense here — "As Above, So Below" wedges you, the viewer, into ever-tighter, ever-freakier holes and crannies. Once the sympathetic claustrophobia kicks in, virtually anything that happens is scary as all get-out. It's a cheap thrill, yes, but a thrill all the same.
Director John Erick Dowdle and his brother, Drew Dowdle, also wrote the screenplay. They relied heavily on lines like "We just have to keep going," and slight variations. The trick is building a lead so monomaniacal that Scarlett will persevere even when, say, tunnels of bones collapse around them, or when everyone seems to be sharing grisly hallucinations. The others in the makeshift treasure-hunting party — a boyfriendy translator, a documentarian and three hired Parisian underworld Sherpas — ought to know better than to continue following. Yet this is a mousetrap of clever construction. This labyrinth filled with generations of French corpses keeps contorting and closing up behind our travelers. Offered the choice between quitting and continuing deeper into an escalating black maze of creepy awfulness, the only logical choice, as stupefying as it often seems, turns out to be the latter.
Dowdle does a serviceable job coaxing naturalistic performances out of his cast, all relative no-names whose acting credits include a lot of television, if that. The pace doesn't slack, even during stretches that could mostly be deemed "slow," if in fact six people weren't continuing to traipse further into an endless cave. Speed helps us move past the spotty logic. Why the hell did they just do that? Oh, who cares, because they're already onto something else. Even the mystical Christianity that propels much of the quasi-supernatural scares starts to make more sense as the movie trips further down the world's nastiest rabbit hole. Momentum alone can make up for a fair heaping of jibberish.
The tight confines and the hopelessness of burrowing further into shrinking caverns recalls another tight little horror movie of recent vintage, "The Descent." Unlike that spectacle, "As Above, So Below" doesn't belabor the physical torment of its characters; gore stays to a minimum, befitting such obvious influences as the Indiana Jones canon and "The Blair Witch Project." Dowdle knows that in the pitch dark, visuals are often less frightening than mere imagination, which he feeds amply with some of the best sound effects you'll come across in this genre. The sound of a ringing phone, eerie singing, the low rumble of earth and of — are those human voices? Perhaps livestock? — other faraway noises, thrumming up through the ground, adds to the sense of doom constricting our terrified explorers. Horror purists aren't likely to care much for the ending, but as they stagger back out into the light of day, they will feel a sense of relief that at least they're not lost 400 feet beneath Paris anymore.