- There aren't many additional bits, the frames allows to build a wall and provided a couple of doors that are supposed to be glued on the side of the tower.
- The walkways are designed to fit either the "flat" side of the tower or the other one.
- There are a couple of flat tabs that can be used to connect more walls together.
- If you want to wreck the wall you can probably cut through it with a dremel or something similar. (this plastic is pretty thick!).
- These are supposed to touch the wall perpendicularly but you could probably trim the edges if you want to build a less ordinary castle.
The instructions are on the back of the box.
2 x side wall frame: this is used to make both the internal and the external wall (they are the same).
2 x walkways frame: the bit on the top is the actual walkway and those two flat things below are supposed to be glued inside the wall.
1 x crenellations frame: crenellations and a couple of doors to be glued on the side of the towers.