In this movie Napoleon is supposed to play the role of Hitler. Just how Hitler brainwashed people and took over, Napoleon did the same thing. Napoleon brainwashed the animals into thinking Snowball was the bad pig, while really it was Napoleon. Also, just as Hitler made new rules, like making his new race, Napoleon made new rules. He took the rules that Snowball had written after talking to Old Major, and changed them.
The ending on the movie was a little bit different approach then normal. The whole movie was used to show how horrible it is when a dictator comes to power. So near the end the animals finally break away from the "dictator"- Napoleon and hide for many years. But then they go back after Napoleon leaves and build a new life together. So the happy ending ends up taking away from the message of a dictator being bad, because the outcome was happy.
All in all it was a good movie. Using the animals to portray animals has been done since the beginning of time. It is a good way to get the message across, and at the same time entertaining to watch.