This is a very clever film, where you have to think hard, particularly for the first half. The acting (and effects) are excellent. Because of the complexity of the plot, it was only in the second half that I began to (understand) and felt increasingly involved with what was going on.

Brilliant scenes on the beach, flashbacks, imagining childhood, running from erasing memories and at the doctor's. Another part of the film's brilliance was to make the science fiction of memory removal become totally believable. And the progression of the plot never lets up, with constant addition of new aspects right up to the end.

In contrast with some films where reality and fantasy are intentionally confused (which I generally find annoying) this film gives sufficient clues to help the viewer to identify the scenes which are reality from others that are flashbacks or imagination.

A lot of lessons on relationships - particularly the ultimate value of memories, even if they are painful.