How is the Animal Farm movie different from the book?
The 1954 Anglo-American cartoon version of Animal Farm was famous—or rather, infamous—for its happy ending, with the dictator Napoleon being trampled to death by the other animals. The CIA, who funded the project, wanted Orwell's book to be turned into an allegory for the ultimate triumph of Western democracy over Communism.
In the original book, however, the ending is much more ambiguous and crucially, much less flattering to the United States and her allies. Because instead of defeating Animalism (read Communism), the local humans have made their peace with it, happily trading with Napoleon and his gang and maintaining cordial relations with them. Not only have the pigs, in their dealings with humans, become more recognizably human, but the humans have also lowered themselves to the status of animals in developing warm political and economic ties with the Animalist regime.
As this message would flatly contradict the Cold War narrative that the 1954 cartoon was meant to convey, a different ending had to be found, one that maintained a much clearer distinction between the forces of good and evil.
There are two movie adaptations of Animal Farm, one made in 1955 and one made in 1999.
The 1955 film was animated, and it was covertly sponsored by the CIA. This film is arguably the closer to the original book of the two. However, it does have a much more optimistic ending, with Napoleon's regime being overthrown by the non-pig farm animals once they have enough of the oppression.
The 1999 film was made for television and shot in live-action. This version is considered a more "child-friendly" variation on the text. The ending is outright happier, with the animals claiming they have "new owners" who will not make the same mistakes as the original farmer or Napoleon, though how they will do so is never specified. This element of the 1999 movie is commonly criticized by viewers, who feel it takes away from the gritty satire of Orwell's original.
So, both versions end with Napoleon overthrown, while the original book has no such optimistic ending, being a cautionary tale.
The plots of the movie and the book follow a very similar trend, as communism spreads throughout the farm and Napoleon takes over and enslaves the others. This is allegorical of the communism gripping the Soviet Union and other nations under its grasp. However, there is one glaring difference—the ending. Orwell's original work shows the ending as a continuation of the servitude trend, leaving things ambiguous and also more frightening than before, as the animals not only have animal rulers, but they have begun making deals with the humans, making things just as bad as before.
In the film version, however, Napoleon is trampled by the other animals, and this is supposed to be an uplifting ending showing the triumph of democracy. However, this is contrary to Orwell's original cautionary tale about the evils of communism.
There was a movie version made in 1955, but I have not seen that one recently so I will discuss the more recent made-for-tv adaptation from TNT in 1999. One of the most significant differences between the two versions is in the narration. The book has a third person narrator that is not quite omniscient. The movie is narrated by Jessie, a Border Collie.
The plot of the movie basically follows the book, although there is some creative license taken. For example, the movie shows propaganda films made by the pigs after they discover that the television keeps the animals entertained.