Disastrously, almost hilariously bad at its job. In most ways it's superficially okay, but it's kind of amazing to see just how badly CGI and 3D can torpedo a horror movie. They should exhibit this in film schools and dissect its failure for the education of future generations.

It's the latest Ring film, of course, which is a bad sign. I like Ring, but it's un-sequel-isable. (Is that a word?) Prequels are fine, mind you. There are only two Ring stories that have successfully been told to date: (a) the original Ring, and (b) prequels about Sadako while she was still alive. However Ringu made enough money to sink a battleship and is undoubtedly the most influential Asian horror movie of all time, so it's safe to say that sequels are inevitable.

There's intellectual interest in how they attack their impossible challenge, though. How do you continue something so perfectly self-contained? The storyline here is actually okay, since it's based on the novel S by Koji Suzuki, the creator of Ring. It's nowhere near the level of the original, but it's coherent and competent, it won't make your brain bleed and its technological upgrade was almost mandatory. Instead of a cursed VHS tape, there's a cursed internet video clip. This means that your iphone can kill you, as indeed can your computer or even a shopping centre video screen that moments ago was perpetrating J-pop.

This had to be done, really. It's in tune with the spirit of Ring, but unfortunately it's also less scary. There's a word for people who open everything they find on the internet. This word is "idiots", or else "people with awesome anti-virus software". The intelligence level drops still further when we reach the following Idiot Loop:

(a) hear about a killer video clip that kills anyone who watches it

(b) spend every waking hour scouring the internet for the flipping thing

(c) die

However I have no problem with the backstory of why Sadako's returned and why the world's in danger. I like Sadako. She's the heart of the franchise, after all. Broadly speaking, I think the screenplay works, although I'd have liked to feel more of Sadako's rage and I think the storyline leaves too many opportunities for a ham-fisted director to make the film look silly.

I see it's time for me to start talking about the production. The guilty party is Tsutomu Hanabusa, which unfortunately isn't an anagram of "I Have No Talent Whatsoever".

The 3D kills the film. (Caveat: I was watching in 2D, so it's possible that it's a masterpiece if watched in 3D as the movie-makers intended. Ahem.) Specifically, the entire film looks too bright and plastic, especially in the 3D money shots. I disliked the flying laptop hanging in mid-air, I rolled my eyes at the glass fragments and I'm downright shocked at their mishandling of Sadako being tipped down the well. That's the cornerstone of the franchise! Here, it's unconvincing. It looks like a special effect.

This kills the atmosphere. I wasn't in the story at all, although the Idiot Loop didn't help either. One scene that should have been shocking just made me wonder, "Is that a prankster?" Satomi Ishihara starts investigating the video clips, after a bit of slightly tiresome plot circling in which she has trouble processing reality that doesn't fit into her idea of how the world works. Sadako starts popping out of video screens and... um, doesn't kill as many people as you'd think. She repeatedly fails to nail Ishihara, for starters. This will make more sense on a rewatch, but on first viewing it just makes her look ineffectual. Her tendency to disintegrate into a cloud of harmless CGI butterflies doesn't make her any scarier either. (No, I'm not joking.)

Eventually Ishihara and a cop go looking for Sadako's well and find it way too easily. They're attacked by plastic-looking CGI bugs, then by Sadako Spider Monsters that will make you think better of that CGI-ified Mark Gatiss in The Lazarus Experiment. This is the most fascinating part of the film, because Hanabusa is clearly under the impression that he's terrifying the audience... and yet he's absolutely not. We're drumming our fingers and clock-watching. The special effects are like an inoculation against fear. This makes the film almost funny when you're staring in bewilderment as Ishihara dutifully screams, cringes in cupboards and otherwise does all the things you'd expect of a horror finale. Hanabusa's ticking all the boxes except the one marked "has any effect on the audience". You'd have more emotional reaction to a Lego animated parody.

No, I tell a lie. There's an effective moment when Ishihara gets pulled down some stairs. That's got to hurt... and it's also the one bit that doesn't look like Yet More CGI.

Oh, and the Sadako Spider Monsters can be killed by iron bars or (you'll like this) Ishihara's screams. This is what I was talking about when I said the script was offering hostages to fortune. Stuff like that didn't have to cripple the film, but it's another handicap when everything else is so unconvincing.

As for the acting, the leads are too young and pretty. Satomi Ishihara is a teacher, but you can hardly distinguish her from the students in her class. She's also boring. Meanwhile the young men in the film are Koji Seto (lead vocalist in J-Rock band Tetra-Fang) and Yusuke Yamamoto (the latest version of Great Teacher Onizuka). Coincidentally they were both in Kamen Rider. However that said, I quite liked Seto.

I don't get the butterflies, though. There's clearly a meaning there, but whatever it is, the film isn't conveying it.

In quite a few ways, this film is perfectly competent and even arguably good. If nothing else, Sadako 2 3D is in post-production. If you can ignore what's in front of your eyes, there's a perfectly decent storyline here that does a respectable job of keeping alive the franchise and has layers to be discovered on repeat viewings. Even the production has its good points. I liked the cursed video clip itself. I like the childhood flashback, which is the one passage where I think the film comes alive. There are moments where the film manages to be scary, while there are still things to enjoy when it isn't managing that. Being hunted through a building by Sadako Spider Monsters is kind of fun, in a low-rent video game way.

However I think it's a train wreck.

In the English version, apparently Yamamoto says, "It's showtime." I'm so glad I watched in Japanese.