It's well written, that's for sure. I think it's the only IF I've read that has children with realistic childlike minds. I'm not fond of multiple POVs - it's usually enough to scare me off a work of fiction, but it's not the case here.
The only thing that I don't like is mechanic of coping mechanisms. Especially the laughter part. In this case madness reads as synonymus to craziness, which is basically a not-so-nice name for a mental illness. It feels like the game is implying that you can choose to become mentally ill? I know I'm probably looking too deeply at it, but I can't help it. It bothers me quite a lot. Especially since coping through humour might be one of more healthy mechanisms (not saying it's healthy, just that it's less harmful than a bunch of other options). I'd redo the mechanic to be something more like... Externalized (destructive) vs internalized (self-destructing), uncontrolled emotions vs emotionless, avoidant vs conflict seeking. Something like that?