This film has a lot of surprises - many 80s horrors seemed great at the time, but weren't that well made in retrospect. This one actually has some amazing sound design, and captures the groaning sounds that you hear from a house at night, when everything is quiet, which I think was part of the directors intention. Also, some of the special footage of circuit boards and the inner workings of technology, created by the Oxford Scientific Film company, are quite intriguing to see. This film really does do what many films should, where your eye is just following the subtle action, not sure exactly where it is going to end up, but mesmerized by what is happening.