Pinball level:
On the Pinball level where you are avoiding the balls going back and forth, jump if the side-to-side pinball is approaching you. This way, Dirk will not slow down and you can avoid getting hit by the big black ball following you.
The Dragon's Lair:
When the dragon tries to light you on fire with his mouth, run close and opposite to where the it opens its mouth. Once the dragon has completed with its fiery salvo, run out of his claws reach and face him. The dragon will then directly shoot out the flame that you have to catch with your magical sword (press Guard). Press Attack to release the fire from the sword to cause the dragon pain. Once the dragon is vulnerable, slash it with your sword once or twice. Run out of its way when it recuperates. The process will start again about five times. During the second bout, he will fire two salvos. You can then catch the fire with your sword. During the third bout he will fire three salvos. You can then catch the fire with your sword and so on.
The Impossible Room:
This level is not really that difficult. Remember -- everything is a mirror reflection of the rooms that seem upside down while you are looking up. Get familiar with the behavior of the room and knock it out. However, the difficult part is figuring the locations of the other rooms to get out of this room. The first two are easy because you stumble across them. When you get the Dragon's Eye (so you can see hidden doors), look for an eyeball on the wall. When you see it, use your Dragon's Eye to find the opening. There are only two hidden rooms in the Impossible Room. Look carefully -- one room has bonus items you need. The second room takes you to the Lizard King. When you get the Dragon's Skin (armor against fire), fall down the hole that has fire billowing up on the bottom floor. This will end the Impossible Room and will take you deeper into the castle (Lava Level).
