Let me just start off by saying that I absolutely loved the book "Flowers for Algernon", which we read in my lit class at school. It was probably the best book I've ever been forced to read. Also at our school, they made us watch this movie after finishing it. I found this film at best a poor adaption of a great novel and at worst, a disastrous attempt at surrealist film-making.
First, the positives: The actors, especially male and female leads are excellent and have a definite chemistry together on screen, however they seem a bit confined by the material they are given to perform.
Now, the far more lengthly section of my review: the negatives. 1. Cinematography. The whole movie seems to have been shot in a style to suggest being on a bad acid-trip (not that I would know the feeling.). Many scenes are an endless, ridiculously over metaphorical montage where it would have been much simpler and more effective to use a more straight forward approach. For some odd reason, the director also decided to use a split screen effect at certain arbitrary points in the film for no apparent reason other than possibly the notion that it looked cool.
2. Writing. This is probably my biggest problem with the film. The writing in the movie is simply incredulous, seeing as it not only departs from the book in unnecessary ways, which I will detail later, but it also changes the plot in ways that make no logical sense, such as changing it so that the doctors don't tell Charlie that the effects of the operation may not be permanent, not something a 20th century medical professional is likely to do given that a patient must give informed consent before undergoing an operation. The beginning portion drags on, filled with scenes of Charlie doing childish activities such as playing on a slide or driving bumper cars to the point where one feels like jumping up on one's chair and screaming "We get it! He's retarded!". The most nonsensical plot twist is the series of scenes in which Charlie, not being emotionally developed, tries to force himself on Ms. Kinnian and is, as a result, slapped and called "A stupid moron", then departs on a motorcycle trip for no readily apparent reason and comes back and is suddenly sleeping with Ms. Kinnian, whose fiancée just magically disappears, which leaves the audience scratching its head and saying "Didn't she just slap and insult him two scenes ago? I wish my life worked like that."
3. The Ending. I have given this it's own section because I feel it deserves special attention. At the end of the novel, the reader basically has two ways of interpreting it: Relocation or Suicide (the latter being my preferred interpretation). However, this version removes all of the guesswork by simply giving you no clues as to what happens after he regresses back to his former state. Instead, you get a long, stretched out scene in which he is chased by his former self through long, white hallways for about five minutes, and one is left with a similar reaction I mentioned having during the beginning portion. This is one of the few movies in which I have been shocked to see the end credits, as it just ends with a freeze-frame of Charlie on the teeter-totter and leaves the story completely unresolved.
I'm sorry if the above review seems a bit rantish, however these are simply my criticisms of the film. If you enjoyed it, then that's all well and good. To each his own.