Made by and for aficionados of ’80s-era sci-fi/horror thrillers, “Harbinger Down” ranks somewhere between self-consciously cheesy SyFy Channel fare and better-than-average direct-to-video product in terms of production values, performance levels and overall ability to sustain interest while generating suspense. Theatrical exposure will be fleeting, but this small-budget, high-concept trifle could attract home-screen traffic if favorable word of mouth is sparked by the enthusiasm of genre-friendly websites and bloggers.

Many au courant creature-feature devotees already are aware of this B-movie’s backstory: Writer-director Alec Gillis raised initial funding through a Kickstarter campaign by promising fans an old school opus with an absolute minimum of CGI, and an abundance of animatronics and practical effects. “Harbinger Down” delivers on that promise, more or less, and the quaintly retro look and feel of the film doubtless will elicit knowing smiles from many nostalgic viewers. And mainstream audiences? Well, the more cinema-savvy may be amused by the industriousness of filmmakers who appear to be working on a shoestring budget as frayed as any allotted to a Roger Corman-produced New World release of yesteryear.

The plot, which owes much to “Alien,” John Carpenter’s “The Thing” and dozens of knockoffs spawned by both, pivots on the discovery of a downed Russian spacecraft in the Arctic wilds by researchers tracking whale migrations while aboard a fishing vessel christened Harbinger. Graff (Lance Henriksen), the grizzled sea dog who captains the good ship Harbinger, allows his granddaughter Sadie (Camille Balsamo), one of the researchers, to store the retrieved spacecraft, and the frozen cosmonaut corpse inside it, in the ship’s hold.

Unfortunately — yes, you guessed it — the corpse contains some nasty surprises. Specifically, long-dormant extraterrestrial parasites who are very mean, very hungry, and ruthless capable of transforming their hosts (i.e., human bodies) into sharp-toothed and gruesomely icky blobs of multi-tentacled slime.

After about a half-hour or so of portentous exposition and sketchy character development, Gillis gets down to the serious business of gradually elevating the body count. Sometimes, the unfortunate victims end up looking like figures in a Hieronymus Bosch painting. Little wonder, then, that one character with an especially itchy trigger finger is ready to aim a flare gun at anyone displaying telltale symptoms of infection.

Amid a motley crew of stock characters — the Boisterous Giant (Winston James Francis), the Doomed Black Dude (Mike Estime), the Badass Babe (Milla Bjorn), the Doomed Black Dudette (Giovonnie Samuels), the Supercilious Jerk, aka Victim No. 1 (Matt Winston) — Henriksen stands out by dint of his raspy authority and effortless professionalism. Whether he’s issuing threats (“You pull a knife on my ship, I’ll gut you with it!”) or sounding grandfatherly (“Don’t let fear hold you down!”), he gives the movie much more than it ever gives him.

Gillis keeps “Harbinger Down” moving at a satisfyingly brisk clip, and sprinkles amid the workmanlike dialogue a few mildly clever lines that indicate he has seen the same movies you have. At one point, a supporting player fortuitously discovers that liquid nitrogen can incapacitate the marauding creatures. But when larger doses of the stuff prove necessary, someone duly notes: “We’re going to need a bigger bucket.”

Special effects by Gillis, Tom Woodruff Jr. and Robert Skotak are efficient, if not terribly inspired, and the scenes in which they are employed tend to strike loud echoes of classic moments in better films. Indeed, “Harbinger Down” is more effectively spooky during those stretches when Gillis simply allows lenser Benjamin L. Brown to glide his premonitory camera down dimly lit hallways and across chilly cabins, following characters hellbent on violent demises.