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, you will see a Jump Block. Use it to get on the upper level, kill the Blue Snake, then continue to the right. Slay the Cyclopes then fall down the hole. Avoid the two Bats and fall down on the left. Go to the left and make your way through the blue corridor. Eventually you'll reach a door. Press Up to enter it and prepare to fight Meka.

First boss: Meka
Meka will move back and forth across the room, then stop and spit fireballs at you. Like other bosses in this game, Meka's weak point is his head. To hit him, go to the center of the room while he's moving back. When he's coming into your direction, jump and hit his head, then rush to the left of the screen to avoid his 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 behind him. Try to 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 to the right. Kill the Green Cyclopes on your way. The first holds a Big Heart (which will fully heal you) while the second has the  Key you need to escape the castle. After unlocking the door, you will have to pass through a corridor of 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.