Some comments:
1. Place a tile
"The new tiles are placed the same as in the normal rules." However the rules go on to mention an exception in the same paragraph. Perhaps that statement should be ammended to say that there is an exception?
2. Deploy a follower
It is not clear whether the "upper" parts of the ciy are still considered to be the same city or not - i.e. can another follower be played to the upper part of the city if the lower part is already occupied. The next section (3. Score) seems to indicate that it is possible to play followers to different levels of the city (but again, is unclear).
3. Score - what djdahmer said about meeples and followers (and also note 2). It would be nice if there was a scoring example here to illustrate the scoring mechanics.
Interaction questions:
* Does a builder on one floor counts when adding tiles to another floor?
* When parachuting followers from the CoC, can they go to any floor?
* How do the floors interact with the Towers - can a tower capture a follower on any floor as long as it is within range? How does a tower in a city on a different floor behave?
* Are the different levels still considered a single city for the purpose of wagon movement, farmer scoring and sieges/cathar?
* Do the different levels affect the trade goods?
* What effect does the cathedral have on the different floors?
And something for Korf:
* What happens when Playing with King's Portal?