A dystopian society often refers to a totalitarian one (there is one tyrant ruler), where life isn't so great for the majority of the population. This proves true in chapter 8, because Napoleon is clearly becoming a more and more powerful individual (seen by his manipulation on several accounts: altering the commandments, sending Squealer to distribute false statistics, etc.), which simply reinforces the unpleasant life on the farm (the animals are starving even though they're convinced of the opposite).
