Just got the game, Killed the Naga but I can't get out of the area she was in, the two ctagonal rooms, hallway and little room with a fountain. Need to get out the portculiss or the other door in the Naga's room.

As I recall, there is a lever above the fountain that opens a door - you
may need to look around to find the open door - at the end of a short
previously deadend passage I seem to remember. Welcome to the elevator
maze!
In situations like this the spirit spell that shows "special" locations
is good (can't recall the name).