I'm kinda stuck on something.
In Castlevania 2 when you leave/enter towns the pattern tables change to another tileset. i found out that the memory address $0101 shows the current tileset. and address $CCE9 (0x1ccf9 - ROM) has the data for what tileset to use for town maps. but when I change this value to another, it affects all towns. So what I'm currently trying to find out how to change the tileset for one particular map without changing the other maps that share the same tileset. And how the game knows to store a certain value at $0101 for that map your entering.
sorry if any of this might not make too much sense its hard for a newb to describe.