Dr. Jekyll (Fredric March) has it all. He is engaged to marry into a popular and wealthy family and he is a well respected lecturer. He is also free to air his theories on the human mind; especially where he believes that the good can be separated from the evil in all of us.
After a chance meeting with a prostitute, he believes his life isn't so rosy. He begins to lust after the prostitute and his future father-in-law continues to delay the marriage. Jekyll then decides to take matters into his own hands to rid himself of the evil but only succeeds in creating a violent monster named Hyde.
The result is more of an ape-like creature than of a monster but the change in Fredric March's appearance is astonishing - especially for a 1930's film. March manages to portray the change in his character's personalities well, despite being hidden behind a set of large, almost comical teeth.
Apart from the addition of a romance, which actually aids in getting the torment of Dr. Jekyll across, the film sticks relatively closely to the original story without attempting to go through the laborious effort of trying to explain the events using science. Happily this means the film doesn't drag on with rudimentary 'facts' and concentrates fully on the story.
The romance itself was controversial at the time for being too sexually explicit, especially during the scene where the prostitute is attempting to seduce Jekyll. Personally, I feel this was required in order to show Jekyll's lust (and thus giving the males in the audience something to relate to!) whilst he was being rebuffed by his fiancée’s father-in-law.
Overall, one of the best takes on Stevenson's story.