I’m not sure what intelligent-design proponents would make of Neil Marshall’s horror spelunking picture The Descent, in which slimy, bug-eyed humanoid creatures stalk a group of female explorers whose internal strife poses almost as much of a combined threat as these rampaging carnivores. Regardless, the movie is ample proof that “different” and “bad” need not be mutually exclusive descriptors. While Stateside distributor Lions Gate is aggressively pumping this film — which has already enjoyed a successful run abroad — as the late summer horror entry from “the studio that brought you Saw and Hostel,” they’d be wise to hope for a quick commercial cash-in and cash-out, lest aficionados recall primarily this sloppy, unengaging film during the studio’s next cycle on the genre merry-go-round.

Filmed in Scotland but set in North Carolina, The Descent centers on a half dozen women who reunite, a year after the tragic death of Sarah’s (Shauna Macdonald) husband and daughter, for a sort of athletic retreat of good, old-fashioned unmapped cave exploring. When their entranceway collapses and traps them all underground, the controlling instincts of hotheaded daredevil Juno (Natalie Mendoza, above, rocking the Michelle Rodriguez part) rub some of the ladies the wrong way. Of course, that’s not all with which they have to grapple. As they negotiate plunging gulfs and narrow passages, it comes to their attention that a group of carnivorous creatures is on their trail. Split up from one another, graphic attrition ensues.

The most interesting thing about the The Descent is the manner in which old individual grudges, rancor and guilt warp the women’s collective survival efforts. There is no gung-ho collective. In fact, one heat-of-the-moment death (an accident or murder?) fuels reprisal, and turns part of the action inwards. (Here I was reminded of The Rock’s character of Sarge from Doom, for whom the siege becomes a blanket excuse for unfettered vengeance.) But this is ultimately a false emotional arc, as the women’s motivations seem whimsical and unclear; Juno in particular fluctuates between earnestness and disingenuousness, and Sarah’s catharsis — however inventive in a piece like this — is not ours.

For a movie that attaches so much significance to inter-party bickering and subtle power plays, the dialogue is also often stultifyingly wrongheaded. “If there’s someone down here, maybe they can help get us out!” exclaims a character at one point early on. Yes… if there’s anyone else trapped hundreds of feet underground, they surely have been merely waiting for the right moment to step forward and lead others out to safety.

This is a slightly different point of comparison, but some folks blasted 1999’s The Blair Witch Project — and decried it, a little too loudly, as not scary — because of the jittery camerawork. I’d suggest, though, that while at times admittedly disorienting, it certainly fit within the prescribed narrative confines of the story. The Descent, on the other hand, is a dark and stressed-out mess. The movie is effectively claustrophobic at times, but wholly incidentally so. Marshall fails in consistently defining the spatial relationships of his frames, none of the action cuts together well and the final five to 10 minutes — most of what is being touted in the trailer, not coincidentally — devolves into an orgy of eye-gouging, skull-cracking, blood-spewing, flash-cut violence.

That finale notwithstanding, The Descent is actually fairly restrained and mannered for much of its running time — almost too much so. Heartening, this deep focus on character in such a genre piece. Still, it doesn’t change the fact that none of these characters are particularly sympathetic, leaving the audience to root for their demise, if only they could distinguish the action. (Lions Gate, R, 99 mins.)