There are always differences between original novels and the movies on which are based because of the visual drama required for a screen version. There have been two movies based on Of Mice and Men, the most recent in 1992. The story behind George and Lennie and their efforts to escape homelessness and poverty because "Guys like us... they ain't got nothing to look ahead to" (chapter 1) remains consistent and is an ideal that they can never attain. George must care for the simple-minded Lennie who is a big man but unaware of his physical strength. Lennie feels comforted when the men talk about their dream and the fact that "I got you to look after me..." He wants George to remind him that they are going to have their own place and "live off the fatta the land." Lennie will get to look after the rabbits. The themes generally consider their dream versus their reality, the men's friendship and the trouble that the unchecked Lennie gets into because George is powerless to make him understand.
The movie version shows the vast open space and allows the reader to visualize the lives of itinerant farm workers and their almost helpless quest of bettering themselves. It is also quite apparent how hard their work is. The book is more centered on the personal struggle of these two men and how restricted their choices are which adds to George's feelings of being trapped. Some of the additional points about the differences can be seen when, in the book, the men have traveled by bus but in the movie they travel by train. In the book, Lennie's obsession with rabbits leads to hallucinations but there are none in the movie. In the movie, Curley's prowess with a punching bag while his wife looks are is a sign of trouble ahead and gives the viewer an uneasy feeling but this does not take place in the book.
Neither movie portrays the disturbing moment with Lennie and his imagined Aunt Clara and the Giant Rabbit. This robs the viewer of the unsettling feeling that Lennie is indeed crazy. The irrational, insatiable desire he has for the immediate gratification of feeling soft objects is not safe and infantile. It is based in a frightening and dark place in his broken mind.