I’m not going to over-simplify and proclaim that making a good ninja movie is the easiest thing in the world. But I never would have guessed that doing so is as difficult as James McTeigue’s Ninja Assassin makes it appear. This is a big-budget movie with a top-flight crew and a star blessed with undeniable magnetism, not to mention the R-rated freedom to provide the copious blood and gore that so many genre fans crave. Yet it plays no better than a cheap direct to DVD feature. Ninja Assassin is a forgettable throwaway, a waste of creative talent and the audience’s time.

Like a relic from old Hollywood, only with a lot more blood, the film exists as a would-be star-making vehicle for the Korean actor/pop star Rain, who impressed the Wachowskis and producer Joel Silver while working on Speed Racer. The biggest surprise of this film is that, with respect to their estimation of Rain’s potential, Silver and the Wachowskis weren’t out in left field. Rain has the raw physical prowess to make a career as an action star, and while there’s nothing in Ninja Assassin to say he can actually act, his strong silent persona here should be enough to carry a film or two.

Then again, it doesn’t carry Ninja Assassin. But I’m not sure anything could.

Legend has it that this shooting script is the result of J. Michael Straczynski rewriting a previous script draft in 53 hours. That feels generous; I would have guessed he penned the movie over lunch. What we’ve got is the origin story of a ninja, played by Rain, and the intertwining tale of two Europol agents who attempt to investigate and bring down a modern clan of shadowy killers in black pajamas. The story is merely an excuse for bloodshed, a fact underlined every time the agents Mika (Naomie Harris) and her superior, Ryan (Ben Miles) pause to cough up inane dialogue.

The overly grim bare-bones story doesn’t kick in until after a bait and switch opening promises more gratuitously gore-soaked action than the movie is able to deliver. A ninja attacks a room full of Yakuza wankers; the first swordstroke cuts a man’s head in half. The slice is an adrenaline jolt; that execution of an unflinching dismemberment plan is all we’re really here to see.After that cut, the gets very little right. A few shots effectively compare the ninja clan to xenomorphs in James Cameron’s Aliens, and there’s a neat turning point where a force of ninja are reduced to cannon fodder when floodlights are turned their way. Ninja work in shadow and silence, and they shouldn’t be invincible in any condition. But that’s all I can check off in the positive column.

Slapdash plotting and subhuman dialogue delivered with po-faced determination by incapable actors: these are not elements that are foreign to the genre. They’re so not foreign that they’re not even deal-breakers. Competent acting and scripting is always welcome, but this is a ninja movie. All that counts is the choreography, the complementary effects and the camera that catches it all.

After that first kill, none of the action is brought to life with any verve. There’s no fun, no ideas. Torrents of CGI blood and limbs lead to an easy comparison to the films of Ryuhei Kitamura, but the big point of comparison is what Kitamura’s movies have that McTeigue’s lacks: energy and attitude. By all the common standards — scripting, acting, film craft — Kitamura’s Versus is a bad movie, or at least a very amateurish one. But it has buckets of ideas and boundless energy, and just a little of each would have made Ninja Assassin infinitely more entertaining.

The film is grim and gritty, overly dark and thinner than the rice paper in a shoji screen. Rain’s backstory is wasted on a love story the film has no hope of selling (yep: the ninja hero is in love with some chick) and the modern sequences are full of dreary Europol agents. Mika and Ryan may be the least memorable cop duo I’ve ever seen on screen. I’d rather watch Turner and Hooch fight ninjas. (Actually, I do want to see that.)

The photography is terribly dark. The reason is irrelevant; the result is that McTeigue shoots nearly every moment of combat with the participants drowning in shadow. At times, that is ideal, as when a few ninja are flitting in and out of shadow. Generally, however, it’s counter-productive. It may have eased pressure on the budget, but the blanket of darkness thrown over the movie makes each fight scene play like a spastic parody of martial arts. The choreography, perhaps impressive on set, looks on screen like a bunch of stuntmen frantically waving their arms. All the CGI swords and blood are very apparent as later additions.

I really suspect the dark is meant to hide a severe lack of imagination. Star-making intentions aside, the only real reason to make this movie is if you have a notebook full of ideas for shredding the human body. But both Rain and his enemies just slice and slice and slice. It’s numbing enough to put a guy to sleep. If Joel Silver wants to make a star out of Rain, you’d think he’d start with coming up with something for him to do.