This film has dated well and still has the power to keep the viewer in suspense. Genevieve Bujold gives a convincing performance as the lead,Susan. Michael Douglas also puts in a good showing. Another memorable performance comes from Elizabeth Ashley. I will not go into plot detail and spoil the fun,but can tell you that this is a top quality production. There are moments of terror that I had forgotten about since last seeing this. The settings are everyday places,but are filled with menace.The Jefferson Institute where the final scenes take place, perfectly evokes a sense of coldness and ruthlessness.
This movie is based on a novel,and has translated well to the screen. This is a classic of 70s cinema sci fi.