The first two films of Duncan Jones, “Moon” and “Source Code,” might have been little more than extended “Twilight Zone” episodes, but they were human stories that, however out there they were, a viewer could relate to. With “Warcraft,” obviously intended to be the first installment of a projected franchise, he proves that he can handle a big, effects-based extravaganza efficiently enough, but otherwise the picture is pretty much a bust. An adaptation of a long-running video game, it comes across as an unholy mash-up of “The Lord of the Rings” and “Star Wars,” and Jones’ attempt to add some humanity to the splashy but empty exercise comes across as a fool’s errand: presenting nonsense like this with such seriousness only makes it more ridiculous.

It would take a user’s manual to understand all the plot elements of the script constructed by Jones and Charles Leavitt—though dedicated players will probably find them easy to follow—but the action centers on a medieval-like fantasy world called Azeroth, where a number of independent human realms have long lived in peace. The most important of them is Stormwind, ruled by wise King Llane Wrynn (Dominic Cooper) with the aid of his knightly right hand Lothar (Travis Fimmel) and protected by a powerful wizard, the guardian Medivh (Ben Foster). Unfortunately, Azeroth is threatened by the otherworldly realm of Draenor, inhabited by orcs, huge warriors controlled by the evil warlock Gui’dan (Daniel Wu), master of a dark form of magic known as The Fel. Gui’dan plans to send the orc horde through a portal into Azeroth to conquer the human world. Only one orc seems to have misgivings: Durotan (Toby Kebbell), chief of the Frostwolf Clan, who has come to believe that Gui’dan is a destructive influence on their kind, and is ultimately instrumental in freeing Garona (Paula Patton), a self-proclaimed half-breed who had been enslaved but will become an ally of the humans in their fight for survival. Another player will be Khadgar (Ben Schnetzer), an apprentice mage who has abandoned his studies at Azeroth’s reclusive wizard monastery and come to the Stormwind court to lend his youthful powers to the struggle.

If all this sounds insanely complex and more than a little absurd, rest assured it’s only the tip of the iceberg, and there are plenty of other humans and orcs to contend with as the narrative grinds on. Jones manages to keep most of the goings-on—which include multiple confrontations, betrayals on both sides and many displays of magical prowess that involve the blasts of colored electrical energy that have been all too familiar since “Return of the Jedi,” along with, if you can believe it, a gigantic golem in the final act—as clear as any director could hope to. But when he attempts to add moments of emotional resonance—one involving the fate of Lothar’s handsome soldier son Callan (Burkely Duffield), another that of Durotan’ and his wife Draka (Anna Galvin), who’s just given birth to his cute-as-a-button son, a third that of King Wrynn and Garona—the attempt to invest the goofy happenings with real feeling is likelier to evoke snickers rather than tears. And when a Moses-like coda rolls around, they should turn into gales of laughter.

The cast has to be given credit for keeping reasonably straight faces in material that might have encouraged them to show that their tongues were firmly in their cheeks. Fimmel, who has some previous experience with such period stuff from his TV work, makes a stalwart if frenzied hero, and both Cooper and Schnetzer provide contrastingly soft-grained turns. On the orc side, all are constrained to a considerable extent by the heavy makeup (which includes something like tusks or reverse fangs that must have inhibited the ability to deliver their lines), but Kebbell and Patton certainly manage heroic poses. Most disappointing of all is Foster, an actor who ordinarily brings some excitement to even smaller roles but here is so laid back that he’s barely recognizable; with his long hair and beard, you might think he was auditioning for the role of Jesus, and not in moneychangers-at-the-Temple mode. Glenn Close shows up for a single scene in which she attempts to hide her face with a hood, like the emperor in “Jedi.” One can sympathize with her effort to grab a paycheck while remaining anonymous.

All of them, in any event, are playing second fiddle to the special effects, which with some exceptions are quite good. There are a great many scenes of crowded battle, and the team supervised by Bill Westenhofer, Jeff White and Jason Smith don’t fumble too often. (It must be said, though, that the sequence toward the close in which Medivh activates his golem is no better than that in which the monster was animated in the recent “Victor Frankenstein.”) The more conventional visual work—Simon Duggan’s cinematography, Gavin Bocquet’s production design, the art direction supervised by Elizabeth Wilcox, Mayes C. Rubeo’s costumes—is also solid, though the aural aspects, including Ramin Djawadi’s bombastic score, reach ear-splitting levels, particularly when heard in IMAX format, where the 3D also blurs some of the busier images.

Presumably there’s a built-in audience for “Warcraft” from the millions of gamers familiar with the property, who are perhaps still interested in it. For anyone else, though, the attraction of this overblown exercise in derivative fantasy would seem to be minimal. Certainly it represents a stumble for Jones, a promising young director who has fallen into the same trap that seduced Josh Trank, the helmer of last year’s abysmal “Fantastic Four” reboot—the chance to prove that you can handle a Hollywood behemoth that might spawn a lucrative franchise.