General Hints
To enter Castle 2 use the unlock spell.
To enter Castle 3, wait until the shark in the moat swims to the right of the drawbridge, then cross.
To get into Castle 4 wait until dawn.
You can not get into Castle 8 until dusk.
To build up experience points find the room in Castle 2 with a coffin standing up. Approach it and a ghost will appear. Keep doing this to build them up.
In Castle 6 you will come to a door that cannot be opened with a key or magic. There are four switches, two on the left side and two on the right side on the door you came in. Picture them as 4-3-door-2-1. To open the door push the switches in this order 1, 2, 1, 4. You will hear a click.
When you talk to Princess Haaggkha she will give you the Dragon Sword and Dragon Armor. When you go to see her, get rid of old items to make room for them.