If you like sci-fi that requires some thought and investigation rather than just being amazed by the effects this is for you.
You can guess the main plot twist quite quickly but there's a lot more to discover with some careful viewing and a very satisfying ending that will leave you contemplating how it would feel to be the main character in the last few moments of the film.
Although shot in the early 70's, the futuristic world, which now looks dated, makes a lot of sense in light of the plot and is surprisingly future proof given the overall premise (how we think things will be, not how they are). It would really be a stroke of genius if this was deliberately designed by Fassinder, one suspects, however, he was heavily influenced by Alphaville, simply using futuristic but modern buildings that reflect the ideas of the future at that time, i.e., cheaper than building new sets!
The accompanying documentary is very revealing with regard to clever casting decisions which, unless you were living in West Germany and at least in your twenties when broadcast, won't be apparent.
Each part exists on a separate disc and there's a definite feel of an original film plus a very good sequel. There are prominent 'cut off' points exactly half way in each part which suggests it may have been originally planned as a four part serial or these are spaces designed for 'non-intrusive' commercial breaks.
The only negatives are, a few marks on the film that should have been cleaned up (in the documentary it shows them making the decision not to!) and occasionally over-the-top audio cues which are slightly jarring. However, most of these faults are in the first twenty minutes and soon forgotten.