Environmental Preservation
As a premise, this series is written around the ferocious strength of nature. What happens when the Earth turns on the people? Atwood is writing in a sort of natural post-apocalyptic setting where people have turned on each other in an extension of the pattern of misuse they originally directed on the environment. People like Zeb's father devoted their lives to the exploitation of natural resources, without once caring about the cost. In contrast, the protagonists -- the survivors -- are all committed to the preservation of the natural environment, which movement is perhaps best characterized in the foundation of God's Gardeners.
Religious Hypocracy
For this theme, the reader must consider two groups of people. The first are the Painball advocates. Although the common people fight in the arena, the actual organizers remain above the violence. They are not subjects but authorities. Rather than practicing the hateful dogmas which they teach, they remain separate from the actual players and thus insulated from the catastrophic internal decay which is the natural end of they're philosophy. On the other hand, there are a more ambiguous type of people who participate in religious hypocrisy. These are folks like Zeb's dad who preach about their faith and then neglect or abuse the people around them. For Zeb's dad, this looks like utter disregard for the Earth. He claims to respect divine authority and literally ignores his own interactions with the created world.
Addictive Violence
In her explanation of Painball, Atwood hones in on this idea of addictive violence. Why do the players keep playing? They can't help it. Given a small taste of vindictive hatred and pure, consequence-free, aggression, they're hooked. With time, the players lose all taste of normal behavior. They have becomes so entrenched in this artificial world of real violence that they have changed the way their brains process pain, especially empathetic suffering. Essentially they've worn away their empathy capacity and replaced it with a hunger for inflicting pain because it brings a kind of high, an addictive satisfaction.
