considering they had no money, this one turned out surprisingly well
the first episode is tense in a way i quite like, and the slow realisation in episode two is quite good too
this story also serves to bridge the gap in character dynamics between the daleks and marco polo, with ian and barbara distrusting the doctor in the former and them all working together in the latter, and i think it does that well
the last scene with the doctor and barbara is particularly good for it
and we end with the gong sound with which you'll be very familiar by the end of the next story