That was pretty wild. I liked it a lot.
An unsuccessful rock band's members are mostly dicks, losers or prone to sabotaging themselves, e.g. by vomiting on stage. One day, they're driving along at night and not really looking where they're going. They run down a zombie. It kills and eats some of the more obnoxious members... so two of the survivors start an all-female heavy metal band with this zombie as the only male performer. It seems to like music and headbanging. They call it Tetsuo.
Incidentally, several of the cast are from a real Japanese rock band, Gacharic Spin. They sound worth checking out.
I'd been expecting this to be a harmless, fluffy comedy with a zombie who'd never bite anyone, but no. These undead kill and they're increasing in number. Things seem normal at the start, but even then no one seems as surprised as you'd expect to find a zombie on the streets. Gradually, the world gets quieter and more dangerous. Our heroines never seem too worried, though, and indeed will cheerfully shout "good luck" when driving past two jogging zombies. That made me laugh. They like zombies. They're attached to Tetsuo. They didn't even notice when he got into the audience and bit someone during their first live show, although in fairness the audience didn't notice either. They're heavy metal fans.
The military created these zombies through illicit experiments, but then didn't keep a lid on things. Whoops. An all-female task force is hunting down zombies (and especially Tetsuo). They're the silliest bit of the film, to be honest. Everything else I could believe in, but not quite those army girls.
The film's taking both of its chosen genres seriously. I respect that. Sometimes this is a proper rock band movie, with story beats like those in traditional band films. Our heroines gradually work their way up to popularity. One girl thinks there are only two kinds of bands: those that sell and those that don't. Another can't imagine singing without Tetsuo and is prone to acts of questionable sanity. (Removing his mouth guard falls into that category, as does an inadvisable choice of hers at the end. She even gets jealous over an undead girl's boobs.)
Also, though, this is a zombie black comedy zombie with a title that's a play on "head banging". Those soldiers definitely suggest a comedy, although they're good enough as boo-hiss antagonists. I was amused by the cool monk with a shotgun. And, of course, no one's paying much attention to the zombie apocalypse that's slowly happening in the background.
The finale involves a rock concert for an all-dead audience. Eiji Uchida is an interesting writer/director. His previous film before this was Greatful Dead, which I didn't like but is still bold and dark. A one-line description of Dead Banging might suggest schlock, but it's a thoroughly professional piece of work. The performances, writing and production values are all impeccable. It's certainly not cheap or trashy. I wouldn't even call it horror. You could show this to anyone, including people who don't like zombie films. I also like the scripting. We don't get to know every band member, but the important characters have depth, issues and sometimes problem parents. The daughter bringing everyone home was a scene that did things I hadn't predicted at all.
This one's worth a look. If nothing else, its one-line description made Misaki laugh.