This took me a while too. If you go to the spot right past where you needed a key you got from the first dragon boss (right before the checkered floor), enter the stairs/door and to the blue/grey brick area. In there go right, and jump the gap to go right again, then in this room lose your hp but DON'T turn to stone.
I second that these are fun games. I also enjoyed "The Perils of Princess Christina' and sequel (mentioned above) if you want more.