Wonder Boy III: The Dragon's Trap/Walkthrough

The game picks up where Wonder Boy in Monster Land left off: you must make your way through the castle and defeat Meka Dragon. Just like the previous game, if you take the wrong route through the level you'll loop around.

Head to the right, slaying Snakes as you go. After passing through the long corridor, use the Jump Block to get on the stone platform. Kill the Blue Snake, go right. Slay the Cyclopes and fall down the hole. Fall down on the left. Go to the left and make your way through the blue corridor. Press Up to enter the door and prepare to fight Meka.

First boss: Meka
Meka will move back and forth across the room, then stop and spit fireballs. Like every other boss in this game, Meka's weak point is his head. While he's moving back, rush to the center of the room. When he's coming back into your direction, jump and hit his head, then rush to the left of the screen to avoid fireballs. The boss' Health Points are displayed in the upper-right corner of the screen. It will take about seven hits to defeat him. After dying, Meka will leave a Blue Flame. Collect as much coins as possible without touching the flame. When you have all the money let the flame hit you; it will transform you into Lizard-Man!

Escaping the castle
Head back through the Blue corridor, and further to the extreme right. The first Cyclope on your way holds a Big Heart (which will fully heal you) while the second has a  Key to the door on the right. After entering the door, pass through the corridor with falling blocks. At the end of the corridor, wait for the blocks to form into giant steps. Climb them then jump out of the screen. Head to the left and leave the castle. You now see more of the game's storyline. You'll end up in a town. Unless you particularly like your new looks you'll need to search for a cure.