The sense of disappointment most people felt in “The Matrix Reloaded” earlier this year is likely to deepen with this third installment in the Wachowski Brothers’ series, which now lands in theatres with a resounding thud. After the fun and freshness of the 1999 original–which (despite what its acolytes later alleged) treated its clever, if rather silly, premise with a sort of deadpan, tongue-in-cheek quality as well as considerable energy–the followup proved far too bloated and self-important, suggesting that the fraternal writer-directors had begun to believe all the fan hype and to take themselves (and their dime-store theorizing) much too seriously. In “The Matrix Revolutions” the slide into ponderous absurdity has accelerated even further. The picture is technically a slick piece of work, of course–impressive in the dark style familiar from the earlier episodes, though like its immediate predecessor it lacks the innovative visual fizz of the initial film (and it doesn’t boast any set-piece as spectacular as the highway battle in “Reloaded”). But from a narrative standpoint it’s the weakest part of the trilogy, a mixture of frantic but empty action and solemn, even more vacuous philosophizing that ends up simultaneously pretentious and puerile. By the close it’s become a kind of pompous joke, a two-hour equivalent of one of Jack Handey’s Deep Thoughts.

“Revolutions” begins where “Reloaded” left off, with Neo (Keanu Reeves) in a state of apparent suspended animation, though he’s actually trapped in a half-way station between the human and machine worlds controlled by a grubby chap called Trainman (Bruce Spence). Meanwhile Zion is about to come under massive attack. So Morpheus (Laurence Fishburne) and Trinity (Carrie-Anne Moss) once again leave the sanctuary to seek advice from the Oracle (Mary Alice replacing the late Gloria Foster, with a barely intelligible explanation for the change). To free Neo from his limbo, the duo, aided by the Oracle’s right-hand man Seraph (Collin Chou), must secure his release from Trainman’s master, the Merovingian (Lambert Wilson). Once liberated Neo traipses off to the Oracle too, who tells him that all will be settled through his confronting the rapidly-multiplying Agent Smith (Hugo Weaving), Neo’s evil mirror image, who’s grown so powerful that his goal is now to destroy both human and machine worlds. So Zion’s motley population–including femme captain Niobe (Jada Pinkett Smith) and homeboy Link (Harold Perrineau)–prepares to defend itself against the machine assault while Neo, accompanied by Trinity, takes Niobe’s ship on an apparently foolhardy journey to Machine City, where, it turns out, his goal is to bring an end to war by agreeing to battle Smith on behalf of both men and machines. On the way, though, he suffers great losses, some at the hands of Bane (Ian Bliss), who’s been possessed by Smith. Nonetheless he’s able to reach an agreement with the machine leader–a roiling, disembodied face that’s amusingly reminiscent of Zordon from the old “Power Rangers” series–and, restored to his sleek leather garb, engages in a final showdown with his nemesis.

The picture, which runs about two hours if one ignores the protracted closing crawls, falls into two parts of about an hour each. The first of them is very slow and talky. Though it boasts some periodic fight scenes, much of it–especially over the first half-hour–is devoted to laborious exposition, so solemnly intoned (and hopelessly muddled) that it will engender amazement of entirely the wrong sort. (Certainly no one who hasn’t seen the previous installments will be able to make heads or tails of this one.) Then at about the half-way point, the story divides into two rotating story threads–the one involving the noisy, chaotic, bullet-ridden defense of Zion, with lots of characters lifted from old World War II potboilers and the “Star Wars” franchise, and the other portraying the Neo-Trinity mission–slow, somber and filled with mystical twaddle and melodramatic self-sacrifice. Though they’re hardly at a high level to begin with, matters deteriorate as the plot drags on, with viewers likely to chortle over some of the howlers that crop up toward the close, expecting to be taken seriously. And when the big battle between Neo and Smith finally arrives, it goes on far too long, makes much less of an impression than the makers obviously intended, and finishes up with a twist that’s supposed to be illuminating but instead is just confusing–a “Huh?” moment.

In the last analysis “The Matrix Revolutions” is little more than a Tinkerbell movie–a story about a Chosen One who succeeds, finally, because other characters believe in him. Unfortunately, the audience never can: what sinks the picture is that it lacks all sense of wonder and never emotionally connects with us. That’s not merely the fault of the actors, though–to be sure–they’re either stolid and statuesque, ponderously reciting the ludicrous lines as though they were as pregnant with meaning as Holy Writ (Reeves, Fishburne, Moss, Alice), or brutally broad (the scenery-chewing Weaving, the leering Wilson and Spence, and all the stock Zion defenders who blast away at the millions of octopus-like “calamari” that invade their city). Rather it’s the result of Wachowskis’ inability to put any human feeling into the film. The entire “Matrix” trilogy is supposed to exalt free choice and the passion of man, but this final episode of the series is as cold, heartless and sterile as the villainous machines.

It’s taken “The Matrix” only three episodes to reach the level of turgid mediocrity that George Lucas didn’t succumb to until his second “Star Wars” trilogy. About the only thing one can be thankful for in “The Matrix Revolutions” is that Jar Jar Binks isn’t in it.