The highlight for this episode, as great as is it is overall, might just be Count Scarlioni's housecoat. Such a luxurious garment almost succeeds in making Julian Glover look like a poor man's Hugh Hefner (although I would posit that Hef is doing a pastiche of Scarlioni, given how suave Glover is in this story).
The housecoat is just one of many little, seemingly inconsequential things about City of Death that make it so enjoyable to watch, beyond the remarkably tightly plotted story that binds the four episodes together. I love how The Doctor figures out Scaroth's plan in the space of a sentence, which would seem like lazy writing in any other story, but because Tom Baker pulls off the explanation with characteristic panache, and because it forces Glover's Scaroth (aka Captain Tencredi in 1505) to realize the cleverness of The Doctor and raise his game to match, The Doctor's quick thinking works brilliantly.
I love the following exchange between Duggan and Romana. "Do you know what I don't understand?" "I expect so". I love how not a boom shadow is in shot during a scene featuring Scaroth and The Doctor, but the entire microphone and boom itself, and nobody noticed for thirty years because we were far too into enjoying the story to be bothered with such trivialities. I love Romana's outfit, the best one she ever wore, and I love how I have no idea how she keeps that hat firmly glued to her head at such a jaunty angle. Most of all, I just love how much fun City of Death is to watch - one of the few times during this Chronic Hysteresis that I've been grinning from ear to ear for pretty much the entire duration of a story.