With this sequel to his surprise 1999 hit, writer-director Stephen Sommers accomplishes something rather remarkable: “The Mummy Returns” is an almost perfect distillation of the essence of the contemporary Hollywood action-adventure comedy. This statement is not, however, intended as a compliment. As fast-paced and slickly mounted as it is, the picture is as cold and soulless as its re-revivified villain Imhotep. Sitting through it is like being trapped in a video game for two hours; the succession of violent, extravagant images flashing across the screen is about what one would experience passing by an endless row of machines blinking away in a mall arcade. Its predecessor wasn’t much–little more than a tacky ripoff of the “Indiana Jones” pictures–but it still had a glimmer of heart and humanity beneath its glossy exterior. That fragile pulse has been totally extinguished this time around.

There is, of course, a narrative of sorts in Sommers’ script: it has to do with the renewed resurrection of Imhotep (Arnold Vosloo) by a cabal of followers of his cult, most notably his reincarnated former love Meela, a.k.a. Anck-Su-Namun (Patricia Velasquez) and a oddball curator at the British Museum (Alun Armstrong). Their evil goal is to place him in charge of the underworld army of Anubis (a bunch of CGI creatures similar, though in an Egyptian form, to the hordes we saw in “The Phantom Menace”) which was once commanded by the evil Scorpion King (played by wrestler Dwayne “The Rock” Johnson in an elaborate but largely pointless prologue). This scheme brings the baddies up against the heroes from the first flick, genial adventurer Rick O’Connell (Brendan Fraser) and his now-wife, Egyptologist Evelyn (Rachel Weisz), who have pillaged a desert temple and secured a sacred bracelet essential to Imhotep’s plan (the temple scene is obviously meant to recall the opening of the first “Indiana Jones,” but it lays on the destruction so heavily as to be appalling rather than amusing). When Imhotep kidnaps the O’Connell’s son Alex (Freddie Boath), a precocious brat who happens to be wearing the bracelet, they must trail him back to Egypt to rescue the boy; they’re aided in the quest once again by Rachel’s bumbling brother Jonathan (John Hannah), mysterious Egyptian swordsman Ardeth Bay (Oded Bay) and shuck-and-jive pilot Izzy (Shaun Parkes).

The story, however, is nothing but an excuse for back-to-back action sequences, most of them replicas of those in the first flick but many also derivative of moments from pictures like “The Matrix” and the “Star Wars” saga. There are constant chases on foot, by car and even by bus; periodic gun battles; endless near-escapes; and lots of hand-to-hand combat. There are also plenty of special-effects sequences involving rolling clouds, tidal waves and swarms of bugs to serve as threats, as well as CGI armies, not only of Anubis’ dark forces but of apparently skeletal pygmies who attack everyone at one point in a deranged sendup of the Ewoks from “Return of the Jedi.” All of this is stirred together so randomly that it’s often impossible to discern what’s happening or why, and even less possible to care. By the end the plot pot is boiling so furiously with deaths-and-rebirths, shootings, explosions and intercut scenes of simultaneous fights that the noise and chaos become positively oppressive (and seem to go on forever). When Johnson reappears, looking in an animated scorpion state like some demented refugee from John Carpenter’s version of “The Thing” (a rejected take of one of the morphed victims, no doubt), the picture reaches a level of overkill that seems like absolute lunacy, and goes completely off the rails.

Within such a context, characterization and intelligence are absent qualities. The dialogue that Sommers has fashioned is a composite of mystical gobbledegook, clumsy exposition, throwaway jokes so tired they’ll make you groan, stilted romantic banter, pithy foreign proverbs and semi-insulting bits of would-be exoticism. The characters are so threadbare that they make the figures from Republic serials of the ’40s seem positively deep and complex by comparison. Even Alan Silvestri’s music fits the baleful pattern: it’s all brassy flourishes with very few moments of repose, rather like something John Williams would have written if he’d left out all the melody.

As you might imagine, the game cast flounders in the resultant mess. Fraser has never seemed more smarmy; he doesn’t retain a smidgen of his usual bumptious charm. Weisz, who must shift from being a strong woman at one instant to a helpless damsel the next (and endure some really embarrassing fight sequences with Velasquez in flashbacks to her former life in ancient Thebes–she’s been reincarnated too, it seems), is surprisingly nondescript in all these guises. Hannah and Parkes ham it up so broadly that they would be oversized even if one were viewing them onstage from the back of the balcony, while Boath proves a youngster who engenders more irritation than affection. Vosloo and Velasquez do their standard scowling-evil turns (the former should be overjoyed that for a good stretch of the picture he’s represented by an animated corpse while his character is slowly rejuvenating), and Fehr manages the inscrutable hero bit every bit as well as Omar Sharif once did. As for “The Rock,” his nickname seems an apt description of his thespian ability. He would be wise not to give up his day (or is it night) job.

Bigger but far from better than its predecessor, “The Mummy Returns” is an impressive showcase for its special-effects crew, but its puerile story and hectoring direction make it more an overblown amusement park attraction than a movie (Universal City must already have some slam-bang addition based on it in the planning stages). And while roller-coaster rides can be fun, even they need proper timing: they require occasional pauses from the plunges, and certainly shouldn’t drag on for over two hours. By trying to top all the pictures that he’s embraced as models (and there are many) in the excitement department, Sommers merely proves that, even in mindless action flicks, more can actually turn out to be simultaneously far less and too much. A movie as relentless as this one leaves you more exhausted than exhilarated. It’s a sad commentary on current audience habits that it will probably be a smash hit.