Very VERY hard read but SO well written and captivating. Absolutely grippingly captures the horrifically human experience of how we survive through crisis even if our survival is at the expense of others. Maybe even especially so. 

Edit: <spoiler>Read a few other comments and came across one about how the non Argentinian characters were from Axis countries and that had me rethinking a lot of the book. I thought about it as a generic, "this is the horrific stuff people will do to other people" idea... Suddenly I remembered it was written by an Argentinian and that there is a culture potentially connected there... I am probably reading too much into it, but yeah. Reading it in English and being in farm country myself, I kept thinking about this taking place at the ranch next door, which it COULD, but also... some of it would be dif erent if that was the case... Just made me think a little more about it is all.</spoiler>

Also, the puppy part isn't unnecessary, it's very important. It shows how much more they impact him than the actual people he helps kill every day. It shows how much more they impact you than the actual people you've gotten used to reading about dying so far. How eay it is for that to have been normalized.