Bokurano is unlike any other manga I have ever read. I haven't read any of the author's other works, but apparently they are in a similar vein.
For a manga about massive mecha battles, Bokurano is a surprisingly quiet manga. The battles aren't truly important, it's the children and how they mentally prepare for them. Fifteen children, faced with an awful and inescapable fate. They can't run away, all they can do is decide how they will rise up and meet their deaths - and rise they do.
This is what the manga is truly about, dealing with a horrible situation and trying to make the best of it. It is about finding humanity in the most desperate of times, of trying to find meaning in a life that is about to end. In some ways, it reminded me of John Green's The Fault in Our Stars, which is about a girl living with terminal cancer. Her primary concern is her parents, and how they will deal with her inevitable death. Some of the children spend their last days trying to make things easier for their families and friends. The boy who doesn't want his younger siblings to know that he died. The boy who wants to save his friend's life as his dying wish. The girl who fights so that her baby brother will have a world to grow up in, even if she can't live to see it. Others try to find some kind of peace with themselves and accept their fates as gracefully as they can. But these are children, and sometimes it isn't possible to do this. Some children, futilely, try to run away. Others use the mecha as a means of enacting personal revenge, even at heavy costs.
At one point, one of the boys is debating whether or not to fight when his turn comes. He explains to a police officer that he never understood films where a lot of people are killed by a monster or natural disaster, but so long as the hero is alive and laughing at the end, everyone considers it a happy ending. If even one person dies, he considers it a tragedy. The only difference between the hero and the anonymous casualty is that the narration follows the hero, but it could just have easily followed the victim who died. He makes us, the readers, aware of the immense casualties these mecha battles have caused. Early on, numbers of death tolls are thrown out so casually we breeze past them in our hurry to find out what happens next. But the manga reminds us that even the anonymous victims were people who had lives, who thought their own existence was valuable. And they died. That is a tragedy. Even if one of the fifteen survives, Bokurano cannot have a happy ending, because too many have died to reach that ending.
Bokurano is a quiet, sad, surprisingly existential and thought-provoking manga. It won't be to everyone's taste. But that's just fine. Most of modern day manga is cheap, quick entertainment, and that's fine too. Manga is entertainment, first and foremost. But it is such a joy to discover a manga that looks deeper and asks the reader difficult questions, ones I'm not sure how to answer. How do you live when you're going to die? I don't know.