Here is the full list of all 13 Wonder Boy: The Dragon's Trap achievements worth 1,000 gamerscore.
Found Charm Stone in Lion-Man's secret location.
Found Charm Stone in Hawk-Man's secret location.
Slew the Vampire Dragon. Cleared the game.
Slew the Daimyo Dragon.
Slew the Captain Dragon.
Found Charm Stone in Lizard-Man secret location.
Slew the Dragon Zombie.
Slew the Mummy Dragon.
Slew the Meka Dragon.. You've been cursed!
Clear game (Hard mode)
Found Charm Stone in Mouse-Man's secret location.
Found Charm Stone in Piranha-Man's secret location.
Found Charm Stone in Hu-Man's secret location.