I've seen quite a few of these Japanese splatter/comedy films and this one is probably one of the most mad, almost extreme. It's a satire on what Japan would do if there was a zombie-like outbreak and half of the country was quarantined off behind a wall. The fun partly comes from those who regard the zombies as still human and therefore should be cared for, and the others who regard them as no longer human and therefore should be destroyed.
Throw into the mix a poor girl - our hero (Yumiko Hara) - who's mother (Eihi Shiina) becomes the Queen of the zombies (not too much of a spoiler as this happens early in the film), and also a slightly disjointed format for storytelling - I've only watched the Director's Cut of the film, the Theatrical release version may be more linear (both versions on the Blu-ray) - and you have a wild ride where you really won't predict what's going to happen next.
This, like Tokyo Gore Police, is a Yoshihiro Nishimura-directed and written film, and it shows. This man, with a limited budget, can produce films full of inventiveness and originality way beyond the standard Hollywood fare, and more power to his elbow - even if he does use rather too much spurting-fake blood!
Sorry to report that I didn't get this from Amazon - I saw it cheaper elsewhere, which is unusual - but it's a film I recommend, so long as you can stand the inventive, but gory, violence (remember, it's NOT real!). I still prefer TGP though, just for the crocodile girl...