I have, like many people, been very interested in movies, shows and fiction about post apocalyptic speculative scenarios. I saw Anna when it came out; I've thought about it a lot since so I watched it again AND read the book.
This is a different world than we have seen in other iterations of this genre. It is the world, but specifically Sicily, after all the adults over the age of 16 or so not only have died, but also will die. All the kids will age out, and they know it.
It's like a global scale Lord of the Flies. The author of the book was intent on not sentimentalizing the children. They are wild and brutal and feral, they have no sentimentality, no history that they can really remember. They are savage, blunt. Heartbreaking. And beautiful. The cinematography is exquisite; the lighting, the dreamy grunge of everything. The soundtrack and score- impeccable. This is next level story telling, hence it won't be everyone's taste. But you'll see and feel things you never thought you would. It's haunting, and that's probably the highest praise I can give. It stays with you.