Well, one key difference could be in the character development. In the novel, there might be more in - depth exploration of the characters' inner thoughts which may be condensed in the movie. Also, the pacing could be different. The novel may have a slower, more detailed build - up compared to the movie which might need to be more fast - paced to hold the audience's attention.
The main characters' personalities are probably kept consistent. If a character is portrayed as cunning in the novel, the movie would also show that character having those same sly traits. This helps in maintaining the essence of the story from the novel. Also, the central themes like class differences or power dynamics that are in the novel are likely to be carried over into the movie. It gives the movie a similar feel and message as the original novel.