From Brolen:

Kuro & Marco is the first non-guro work from noteworthy guro mangaka Horihone Saizou. The titular story has four chapters. It’s an eccentric one about space kids who live in some kind of bizarre alternate universe solar system, where comets are giant dogs, robot people live in a certain part of the the asteroid belt, animal people live on other planets, and the earth is still ruled by dinosaurs.

The other stories in the book are various thematically unrelated shorts, but it’s worth noting that he still managed to sneak a story in about tearing organs out of live prisoners, even though it lacked explicit depictions of violence (apparently, an actual Japanese practice in the old days).