The film version of One Flew Over the Cuckoo's Nest handles the elements in the novel very well and produces a work that is true to the spirit of the original and largely to the letter as well. Changes have been made, of course, and they have been managed in a way that serves the letter of the original in a more dramatic fashion. At the same time, the film does veer more into overt comedy and is also weighted more heavily toward McMurphy as a sheer personality than may be necessary. However, he is well-balanced against Nurse Ratched so that what emerges does seem a duel between the two. It is less apparent in the film where the power may lie in this situation, for the fantasy element of McMurphy's play-acting is so strong it is seductive and lulls the viewer into seeing the film as less grounded in reality than it means to be, so his lobotomy becomes all the more shocking as a burst of horrible reality into this otherwise near-comic core.
Certain thematic elements have been muted if not lost entirely. The mechanistic nature of Big Nurse has to be inferred from various symbols, from the medicine she metes out a pill at a time to the hydrotherapy machine Chief Bromden destroys at the end to the shock therapy room with which the patients are threatened.
The Combine is alluded to but does not have the holding power it does in the novel. This makes McMurphy seem more the outside hero coming in to entertain the prisoners, in this case the inmates. He is the free spirit who points the way for everyone else, though most are in no position to learn and take advantage of the lesson. The concept of the Combine is now embodied more fully in Nurse Ratched than ever before, and the primary purpose of the powers-that-be is to maintain control.
At the same time, Nurse Ratched cannot be considered any more a fully developed character in the film than she was in the novel. Indeed, the most fully developed character is McMurphy in bot...