The characters in "Flowers for Algernon", and its movie were very much similar; however, there were not as many differences. But one thing i realized, is that Dr. Strauss was a lot older then i had imagined, and in one of the movies Dr. Strauss was a woman. In the movie Charlie lived in an apartment with a land lady but in the story Charlie lived alone. In the movie Gimpy was Charlie's friend and co-worker at the bakery, but in the story Gimpy wasn't mentioned and doesn't exist.
The setting of the story "Flowers for Algernon" and its movie were also very similar aside from the fact that Charlies work place is Donigan's bakery instead of Donigan's plastics factory. In the book Charlie lived in New Jersey whereas in the movie he lives in New York.
The plot had alot of the same basic features. Particularly, Charlie goes to night school, he lives alone he gets picked on by his co-workers and of coarse he is mentally challenged. On the other hand, there are many differences in the plot. In the movie they added the aspect of him trying to make his mother proud and the back story behind that. His flashbacks of his childhood and the story behind that were in fact added on