I randomly bought volume 1 because I love the anime, then went berserk on seeing the first chapter and returned to Book-Off to buy another four volumes. Unusually for me, what I'd loved about it was the art. Kudan Nazuka is a strong artist with a ton of energy and is brilliant at keeping things dynamic with our two very different protagonists... but that first chapter is nearly 50 pages of Rachel Gardner on her own in an empty, sometimes almost featureless building. That could (perhaps even should) have been boring, but it looks superb. Nazuka characterises the space. The artist and the character carry this minimalist (but strong) storyline so compellingly that it's worth studying.

After that, what makes this manga special is its two protagonists. I've never read anything else like them. 1. Zack (aka. Isaac Foster) is a stupid, irascible psycho who wants to slaughter everyone he sees. He's almost uncontrollable. Even he can't usually manage it... and he's not in the habit of trying. Self-restraint is not among his talents. 2. Rachel Gardner is a thirteen-year-old girl who wants Zack to kill her... which creeps him out, so he refuses. His reason is hilariously whacked out. She keeps following him around anyway. They team up, on condition that he promise to murder her once they've escaped from this building.

That's an amazing duo. The narrative's a platonic love story, except with murder vows instead of love declarations. They're arguably healing each other, although they're also both deeply messed up and the manga won't let you forget that. Rachel's revelation is in later volumes (although I remember it from the anime) while Zack isn't joking when he says he can hardly stop himself from butchering her. The manga surprised me with how far it takes the characterisation and its rejection of obvious choices... and I say that as someone very familiar with the anime.

Is it perfect? Hell, no. Zack's ability to survive injuries without medical treatment is implausible, while I got a bit bored by the psycho killers' flashbacks. (Well, the psychos who aren't protagonists, anyway.) Unfortunately, that's most of volume 5. Also, the pacing is shouting "serialised manga". A Western comic would have told this story in far, far fewer pages.

Incidentally, both the manga and the anime are based on a computer game, which explains a lot. The building they're trapped in is absurd and it's hard to imagine anyone in the world deliberately setting that up, but as game logic it makes perfect sense. Lots of levels. You have to reach the end of them. (Apparently the game and the anime have different endings.)

Honestly, this one's amazing.