I was surprised and astonished; surprised that the novel had been successfully adapted, astonished by how great a movie it had been turned into. It wouldn’t do to spoil the story for anyone who hasn’t read or seen it, so I won’t talk about it; also, it would be hardly necessary, because “the story” is not what makes Ishiguro's work great, nor this particular movie. There is no violence, no shouting and no hard language in “Never let me go”, and yet it is one of the most disturbing, most horrifying storytelling that I have ever come upon. One of the great accomplishments of the film is that it recreates that horror by means different from Ishiguro's in the novel, but his method would not have worked on the screen. Another is the way the poignancy of Ishiguro's narration is recreated visually by a combination of the production design, which constructs a world slightly odd and squalid, and the beautiful cinematography, that renders that world in beautiful soft and intense images. The careful exposure results in a very wide range of luminosity, and the extensive usage of a large aperture blurs the background into pools of rich colour, creating absorbing pictures very suggestive of the avid and quaint subjective tone of Ishiguro's first person narrative, which otherwise would be lost to the third person point of view of the camera. The acting is excellent, subdued but authentic. There is no question of realism here, because most of what happens and of how the characters seem to feel about it will strike the viewer as despairingly unrealistic if compared against our own reality, but it is acting that renders characters very faithfully in terms of the novel.
If you read and liked the novel, watch the movie, you will not be disappointed. If you plan to read it, watch the movie afterwards, because the development of the plot relies in part on your ignorance.