Below are the areas that you can miss during a normal playthrough of the game in the order you will come across them. The achievement will not pop up until you click on the "map" button and see 100% at the top of the map screen.

Castle Tower
At the top of the tower, there is a telescope that you can look through to see the forest. This is needed to 100% the tower section of the map.







































"Uninvited" House

IMPORTANT: This can be permanently missed. After solving the puzzles in the house, and leaving you will see that the front door is open. Enter it and you will get a game over. Continue and you will have the map updated with that location. Once you leave the "uninvited" part of the map, you will not be able to return to get this.



























































Themeire Mansion

In the upstairs guest bedroom, use the "Tar Gynthal" spell on the mirror to open a path to the master bedroom. You will have to do this if you want save the imp in your playthrough, but it is possible to miss this room if you don't.








































Gwnenthell Castle

After completing the game, you might notice that the castle in the beginning is still not 100%. You actually can't enter the last location until the very end of the game, when you arrive at Shadowgate.

In Shadowgate, in the hallway before the final boss, use the "Tar Gynthal" spell on the mirror walls to change them to a room. Move into the mirror and you will be back in the castle.