I was surprised to discover that this wasn't straight-to-video, but it's okay. It's taking itself seriously and even wants to be the first of a series, although I don't think any sequels got made.
The protagonist is an ordinary schoolgirl called Misaki with no combat skills. Her purpose is simply to be the audience identification figure and I didn't see why she kept following undead killers, entering yakuza strongholds, etc. Well, never mind. The person who matters is Airi, a girl with stone-cold skin and superhuman combat abilities. Every so often she'll go into spasms as zombie-like grey veins spread across her face and hands, but there's medicine to suppress that. She works for an agency. Her direct superior is a hatchet-faced man played by Kazuyoshi Ozawa who'll suggest eliminating civilians who get inconveniently close to the truth.
Like Reiko The Zombie Shop, this is a Buffy-influenced Japanese film about a superhuman schoolgirl who goes around killing undead. These have three variants: (a) zombies that can be activated and/or remote-controlled by their undead masters, (b) augmented bodyguard zombies that can transform their arms into magic weapons, and (c) Buffy vampires. They've got the same fangs and triangular forehead make-up, although admittedly these ones can survive daylight and don't disintegrate when staked.
The storyline is what you'd expect, but perfectly okay. Everything seems normal and ordinary people have no idea that undead exist, but that's because Airi's a busy girl. There are rumours of a girl who cuts off heads, but those aren't believed by Misaki and her camp gay black friend Takashi (a broad performance from I think an actor who works under the name "Bobby").
Yakuza underestimate Airi. Whoops. A Big Bad has a distressing backstory, although Misaki's right to say that doesn't justify zombifying people and causing deaths. There's also a twist at the end that made me roll my eyes. (It's been done for surprise value, not plausibility. Are we supposed to believe that Misaki's best friends with everyone who matters in the undead world?)
I quite enjoyed this film. You couldn't call it remarkable and there's no real reason to recommend it, but it's achieved its straightforward goals. Airi's brilliant at fighting, but has an empathy problem and no discernible emotions. She should learn to smile. Misaki's engaging, but also a bit of a fifth wheel for significant stretches of the film. Takashi's actually the liveliest character, albeit also a stereotype. If they made more films in this series, I'd watch them.