As other reviewers have said, the strength of CoS is the atmosphere of its setting. Though the author may have conceived the City as part of her own fantasy world; for me she manages wonderfully to capture the unmistakeable ambience of a middle-european capital during the later cold-war era. There is a polished, and almost luxurious veneer, but underneath, everything is curiously shabby and archaic. As the title implies, this is a city whose social structures are founded on lies and secrets rather than anything more substantial and enduring. Even the NPC interactions reflect the careful tones and phrasings of people living with the knowledge that everything they do and say may be observed.
The sense of place and time is so good, it seems almost churlish to draw attention to the slight flaws in the plot; a certain stiltedness that grows more marked the further we get into the story. To say that there were points at which I found myself becoming almost bored, gives a slightly inaccurate and rather picky picture. There was never any real danger I would give up, largely because the sheer depth and accuracy of the setting had me well and truly hooked.
Overall CoS was a very good game and a very enjoyable experience. I just couldn't help feeling that it had the potential to be even better.