Gazing at actor Michael Fassbender’s fine tuxedoed self as he celebrated “12 Years a Slave’s” historic win at the Academy Awards earlier this week, it was hard to believe that seven years had gone by since we first met the dreamy Irish actor, when he played a brave Spartan soldier in the cult pulp classic “300.”

In that film, director Zack Snyder put his bombastic gifts to use in bringing ancient Greece, if not to life, then to some kind of mesmerizingly bizarro, synthetic version thereof. A super-stylized mashup of graphic novel narrative and video-game stagecraft, “300” was a huge hit, launching Fassbender into much finer things (including a longtime collaboration with director Steve McQueen) and star Gerard Butler into a Dante-esque limbo of forgettable rom-coms and middling action flicks.

300: Rise of an Empire” isn’t a sequel to “300” as much as a parallel-quel, catching up with the Athenian-led Grecian forces at the same time that “300’s” King Leonidas and his Spartans are getting their toned tushies kicked at Thermopylae. While no big stars are likely to emerge from the speechifying and gruesome swordplay of this installment, the film does feature at least one genuinely memorable performance by Eva Green, here playing Persian naval genius Artemisia with such gothic bloodlust that the only things she’s missing are fangs and a coffin to sleep in. In “Rise of an Empire,” Artemisia has been sent by Persian god-king Xerxes (a blinged-out Rodrigo Santoro) to defeat Greece and avenge the death of Xerxes’s father, Darius, at the hands of the soldier Themistokles (Sullivan Stapleton). Suffice it to say, things don’t go exactly according to plan.

Based on a still-to-be-published graphic novel by Frank Miller, “Rise of an Empire” has been adapted by Israeli commercial director Noam Murro with alternately crude and canny fealty to Snyder’s hyperventilating original: A series of smashing, crashing seafaring set pieces interrupted by variations on Henry V’s Crispin’s Day speech (or maybe the “Gentlemen, to bed” gag from Steve Coogan’s “The Trip”), this chapter is a dull, monochromatic affair, its dingy gray palette barely enlivened by syrupy blood that spurts, squirts and gushes with metronomic regularity. When the film isn’t sloppily directed, it’s a series of lazy filmmaking tics, including fetishistic slow-motion shots of blood, water and sweat, as well as sundry dismemberments, impalings and decapitations.

It sounds like a blast, doesn’t it? But “Rise of an Empire” is no fun at all — even those famous six-pack abs from “300” seem to be missing a can or two in this desperate attempt to up an already dubious ante. Despite a visibly sincere effort, Stapleton is a non-starter as the brave Athenian trying to unite the city-states of Greece in defending their experiment in democracy. His supporting players are little more than an anonymous tableau of shirtless, grunting dude-itude.

Oddly, for a franchise founded on the bedrock of man flesh and macho posturing, it’s the women of “Rise of an Empire” who make the most impact: Lena Headey, as Spartan Queen Gorgo, makes serious, focused use of her lamentably limited time on screen, and Green rips into her ruthless anti-heroine with throaty gusto, not to mention an endless supply of beautifully draped leather and chain mail. (Who knew Persian barges boasted that much closet space?)

Despite its comic-book sensibilities, “Rise of an Empire” is anything but family-friendly. In addition to its steady stream of gloppy bloodletting, the film includes aggressive sexuality that borders on the perverse, including a ludicrous scene of carnal passion below decks, and a startling moment of intimacy between a key character and a disembodied head. How do you follow a scene like that? “Rise of an Empire” makes an attempt, but it only looks sillier the harder it tries.

R. At area theaters. Contains strong, sustained sequences of stylized bloody violence throughout, a sex scene, nudity and some strong language. 102 minutes.