"300: Rise of an Empire" is the long-time-coming follow-up to "300," Zack Snyder's 2006 sword-and-sandal slaughterfest. Severed limbs once again fly; skulls split wetly; and fat gobbets of slo-mo blood squirt through the air, this time in 3-D. You'd expect maximum flesh-rending here (and, of course, maximum CGI), and if anything, the movie over-delivers. But who would expect a new technical level of epic gut ripping or the vividly smoldering Eva Green, who turns up — in and out of various black leather outfits — to virtually take over the picture?

The year is still 480 B.C., as it was in the previous film, where we saw the Spartan King Leonidas (Gerard Butler, only a flashback here) and his modest band of Greek warriors getting tromped at the Battle of Thermopylae by the vast army of Persia's King Xerxes (Rodrigo Santoro). "Rise of an Empire" isn't really a sequel to that story; it's more of a "meanwhile." Now the focus shifts to Athens, where the hunky naval commander Themistocles (persistently bare-chested Sullivan Stapleton) is attempting to rally the independent Greek city-states in united resistance to the Persian onslaught. He's not having a lot of luck, especially with steely Queen Gorgo of Sparta (Lena Headey), Leonidas' newly minted widow.

This is probably not a movie for history nit-pickers, but they can stick with Herodotus (himself something of an approximator). "Rise" — once again drawn from Frank Miller's comics — is an action blowout with a rich pulpy narrative, and it's set in a computer-generated world that demonstrates how far digital effects have advanced over the past eight years. The huge heaving seas on which so many of the naval battles take place here set a new standard for maritime mayhem, and new director Noam Murro thrusts his cameras into the middle of all the uproar with unflagging energy and invention. (He brings off some knockout shots, such as the one in which we see battling sailors staggering about on rolling, blood-slicked decks and then Themistocles leaping into the fray on a horse.) Murro also has a notable talent for poetic effects. (He shifts underwater to show us debris and corpses eerily drifting down in the aftermath of one calamitous encounter.) The movie is thick with gruesome visual wonders.

The script, by Snyder and his "300" collaborator, Kurt Johnstad, is highly amusing in its creation of a gaudy back story for two of its central characters. We meet Xerxes as the young son of the dying King Darius (Igal Naor). Xerxes has long been outshone as a fighter by his fierce adoptive sister, Artemisia (Green), whom Darius rescued as a girl from years of Greek enslavement. Darius has said that only the gods can defeat the Greeks, so Artemisia undertakes to transform Xerxes into a god — which turns out to be not so difficult as you might think. She leads him off to a mysterious cave of weird hermits, where he steps into a magical pool and emerges as the Xerxes we've previously come to know and love — heavy with bangles and nose rings, resplendent in tweezed brows and eyeliner, and homoerotically hot in tight golden shorts. Thus dressed for success, he launches his invasion of Greece, with Artemisia at the head of his fleet.

Green is a marvelous warrior woman, soul-kissing severed heads and spitting out ripe lines such as: "Humiliate the Greeks and lay waste to their tiny ships!" But although Artemisia's forces far outnumber those of Themistocles, his wily strategies continually frustrate her objectives. Finally, she summons this cagey opponent to her ship for a timeout parlay in her quarters. This doesn't change much, battlewise, but it does lead to what must be the wildest sex scene in any action movie ever.

For viewers who know in advance what they're getting into and are happy to get into it, "Rise of an Empire" should be great, bloody fun. The movie is over-the-top in just about every way — and it has to be said that after an hour or so of brutal, nonstop frenzy, you're liable to feel as if you're being beaten down with battle hammers. Hard-core fans can take that as a recommendation.

Kurt Loder is the film critic for Reason Online. To find out more about Kurt Loder and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.