The gleaming black Xenomorph of the “Alien” franchise—eyeless, serpentine, a creature of claws and dripping fangs—is certainly one of sci-fi cinema’s most recognizable creations. And the creature’s had a long lifespan since its first appearance onscreen. Its best outings—Ridley Scott’s initial space-slasher flick and James Cameron’s shoot-‘em-up sequel—are indisputably genre classics, even if its later movies were pretty lackluster (we don’t talk about “Alien vs. Predator”).

With “Covenant,” Scott aims to bridge the time gap between 2012’s woefully underappreciated prequel “Prometheus” and his original 1979 movie. And, true to form, the first third of “Covenant” feels like a straight-up remake of the first “Alien.” We first meet android Walter (Michael Fassbender), who’s in charge of managing a spaceship of outbound planetary colonists. The ever-appealing Katherine Waterston turns up as Daniels, this installment’s protagonist and requisite Wide-Eyed Brunette. James Franco, Guy Pearce, Danny McBride, and Billy Crudup also make appearances, but they’re largely background scenery. (This is an “Alien” movie. You know most of these people are gonna die.)

A mysterious radio transmission unexpectedly draws the crew to the surface of an alien world, where they discover a crashed spaceship filled with traces of a mysterious civilization. People get infected with extraterrestrial spores, monstrous creatures erupt in gory explosions from human bodies, and general carnage ensues.

And then “Covenant” shifts gears, abruptly veering away from its horror-film sensibilities and revisiting topics last seen in “Prometheus.” As it so happens, the planet is actually the burned-out homeworld of the Engineers, the nine-foot-tall aliens responsible for seeding the galaxy with life (and, in the process, creating humankind). Some old friends from the last installment also show up,

(Spoilers ahead. Without them, it’s impossible to do this movie’s themes justice.)

It quickly becomes clear that David (also Michael Fassbender), the castaway android of “Prometheus,” has set himself up as king of the necropolis around him. Obsessed with the concept of creation, he’s labored for years to manipulate the “bioweapon” of the Engineers—the spores that birth proto-Xenomorphs. His goal: spawning a “true” Xenomorph—the sinuous dark monster of the original film quadrilogy, which he views as the “perfect organism.”

This is relatively cerebral stuff, and “Covenant” often feels like an uneasy attempt to blend the narrative styles of two very different movies. The grand themes of “Prometheus”—creation, power, human destiny—are a lot more highbrow than the earthy nastiness of the original “Alien,” and it’s quite clear that Scott’s much more interested in the former than the latter. Thus, “Covenant” ends up tacking on a third act that quickly turns into a retread of the original flick—a xenomorph is stalking crew members through the spaceship!—rather than striving for some suitably operatic height of horror. (Call me overly baroque, but I’d say the climax should’ve been a blood-soaked, hand-to-hand battle against David, fought in a charnel house of creation, decomposition, and rebirth and set to a classical music score.)

That said, “Covenant” really does have some genuinely visionary moments. The destruction of the Engineers’ homeworld, depicted in flashback, is a Boschian nightmare come to life: a sea of twisting limbs, insectile carapaces, and dark mist. David’s laboratory is a bone-chilling, Da Vinci-meets-Leatherface vision of deconstructed human forms. And whether or not his ideas are completely lucid, Scott’s clearly trying to say some very interesting things about God, the body, and sexuality.

If “Prometheus” had Gnostic overtures—disengaged, somewhat malignant creator-beings, or demiurges—“Covenant” doubles down hard on those themes. An important part of Gnostic philosophy was the idea of “emanation,” or a chain of subordinate beings interposed between God and the world. That idea of emanation is the narrative backbone of “Covenant”: from the Engineers come humans; from humans come androids; from androids come xenomorphs. And despite David’s talk of increasing evolution toward perfection, it’s plainly apparent that what plays out is a steady deconstruction of the idealized superhumanity of the Engineers. Humans are more biologically fragile than the Engineers; androids lack the ingenuity and freedom of humans; xenomorphs are nothing but soulless killing machines. Any attempt at subcreation has its limits.

And I’m certainly not the first to note the eerily sexual imagery that characterizes the franchise’s art design. Here, Scott’s seemingly suggesting that the disintegration of human identity goes hand-in-hand with the amplification and exaggeration of human sexuality (in the form of the xenomorph, a being of pure appetitive id). That’s a pretty heady idea, even if it remains only an undercurrent.

(Spoilers end here)

Technically, “Covenant” is satisfying but not groundbreaking, and leans very hard on its computer-generated effects. Occasionally this is great (we get a bang-up, three-dimensional alien battle on a wildly careening shuttle), but most of the time it’s a serious letdown. I’m firmly in the camp of folks who think special effects have actually gotten noticeably worse in the last decade or so: CGI creations move with unnatural speed and fluidity, breaking the illusion of reality. It’s hard to believe, but the prosthetics and rubber monster suits of the 1979 “Alien” really were much, much scarier than anything seen here. (The same could be said of other films in the genre: the gooey effects of John Carpenter’s 1982 monster movie “The Thing” were vastly superior to anything in the CGI-drenched 2011 remake).

When all’s said and done, “Covenant” is a middling sixth installment in a longstanding franchise that’ll almost certainly keep trucking for years to come. As a fan of the series (yes, even the crummy installments), I have to confess my disappointment: Scott simply doesn’t let his ambition carry “Covenant” to the heights it demands. Love it or hate it, “Prometheus” really went all-in on its Big Ideas. I only wish this chapter had been willing to aim as high.

VERDICT: 6.5/10
Not the finest “Alien” series outing, but certainly not the worst.

Normalized Score: 2.4