Sacrifice is perhaps the most straightforward of all the themes in Nothing. There's no metaphor here; people are literally giving up the things that are most important to them. In the case of Oscarlittle, Cinderella, and, ultimately, Pierre Anthon, they actually sacrifice their lives, though not intentionally. Which leads us to ask: if it's not intentional, is it still a sacrifice?
Each sacrifice is exponentially greater than the one before.
The heap of meaning would have looked very different if there had been a rule forbidding revenge sacrifices.