A highly political novel
There is no question that George Orwell intended Animal Farm to be a strong work of political criticism, and it can be viewed as a reaction to various political tendencies he had observed in both Europe and Russia throughout his lifetime. This is already very clear when studying the book itself and comparing it to history, but Orwell also confirmed this intention when he discussed the book later on.
Furthermore, the political criticism of Animal Farm is unusually direct, as the story contains extremely clear parallels to real-life political situations.
Criticism of the Russian Revolution and Stalin’s rule
Animal Farm is entirely framed as a direct criticism of various events surrounding the Russian Revolution, especially related to Stalin’s (symbolised by Napoleon) role in pulling the newly formed Soviet Union in the direction of a dictatorship.
Interestingly, the Russian Revolution itself is at first presented in a relatively positive light. The initial ideals of ‘Animalism’ (= Communism) are very sympathetic - and Mr. Jones (= Tsar Nicholas II) is described as tyrant who does not care about his ‘people’s’ suffering. Orwell does not seem to question that the revolution itself was justified, although he does note that it was a significant issue that the general population might not have been fully aware of the communist ideals and their implications, and therefore did not really know what they were fighting...