Hollywood attempts to capture the tone and energy of eastern martial arts movies have mostly been sad failures—even (maybe especially) made by directors imported for the purpose—and “Ninja Assassin” is no exception. It’s one of those pictures that feels like it originated as a video game, even though it didn’t. But as a studio effort to create a western-friendly version of the ninja sub-genre it could be worse. And it’s certainly preferable to director James McTeigue’s previous picture, the loony, pretentious “V for Vendetta.”

Korean pop icon Rain (who appeared in “Speed Racer,” an inauspicious start), stars as Raizo, who’s broken from the sinister master (Sho Kosugi) who took him in as a child and trained him to become one of his Ozunu clan of killing machines. It’s all a matter of business: for centuries the Nine Clans, including the Ozunu, have provided assassins to anyone with the wherewithal to foot the cost—a hundred pounds of gold. But after an initial kill, Raizo, already bummed out because Ozunu killed his sweetheart (another trainee) for breaking house rules, goes rogue and works as a lone wolf to dismantle the entire clan operation.

All of this backstory is told in a fractured fashion via an avalanche of flashbacks that punctuate the present-day story—a very simple one in which Raizo becomes the protector of Mika Coretti (Naomie Harris), a “Europol” forensics investigator who’s uncovered traces of the clan’s involvement in recent political killings and, along with her boss Ryan (Ben Miles), becomes a target of the group. What follows is a collection of big fight sequences featuring lots of severed limbs and blood splashes, courtesy of the array of weapons (swords, chains and star-shaped throw-thingies) with which Raizo confronts the hordes of black-clad brethren sent against him (and they him, of course). Naturally it all comes down to a final battle back at the Ozunu compound perched on a mountainous cliff somewhere in the Orient, where Raizo has the expected face-offs, first with his older nemesis Takeshi (Rick Yune), and then with his old master.

The flimsiness of the plot is less a problem than one would think, because it’s the fight action that makes a picture like this. Nor is the dour impassivity of the lead character all that unusual, though one must say that one gets no hint of Rain’s range from the result (the younger versions of the character, played in childhood by Yoon Sungwoong and as a conflicted teen by Joon Lee, show a greater variety of emotion). But certainly Rain is a handsome guy with a lean but impressively muscular physique, and his monotonous delivery even of the few jocular lines provided him by the script has a deadpan quality that’s mildly amusing itself—one hopes intentionally.

What hobbles “Ninja Assassin” are other things. One is the general lack of humor; a tongue-in-cheek attitude would have helped, and apart from Raizo’s occasional one-liners, the tone is way serious. Another is the unnecessarily complex structure, with all those flashbacks; and even after the movie’s over, one will be hard pressed to explain the presence of a pre-title prologue, which seems to have no purpose but to allow for a symmetrical twist at the end. And apart from Rain, the cast is pretty much wasted. Harris, in particular, is reduced to the status of damsel-in-distress awfully quickly.

The main flaw, however, lies in the execution of the battle scenes. Not that the participants don’t exhibit considerable dexterity—at least what we can see of them. The difficulty is that the scenes are so muddily shot and choppily edited, and overlaid with so many effects (painted spurts of gore, exploding heads and shorn-off body parts, weapons flying about that were obviously added in post-production) that they come to look almost animated. Not being a particular fan of ninja movies, I can’t say whether that’s a technique common to them, but there’s certainly none of the frisson that comes from watching Tony Jaa do his amazing stunts without wires in full-figure, long-take sequences. The effect here reminds one of a musical like “Footloose,” when we see an actor shot waist-up pretending to dance before a cut to someone else’s legs actually performing the steps. It’s not as pronounced here, of course, but it comes dangerously close.

On the other hand, if “Ninja Assassin” is no prize, at least it barrels ahead without trying to humanize its comic-book characters or deliver a ludicrous “V for Vendetta”-style political message. It’s content to remain simple action junk, which will make it acceptable if that’s what you want.

And if you can take all the extravagant gore, of course.