Here is the full list of all 30 Battle Princess Madelyn achievements.
Get eaten by the tentacle monsters
You've killed 100 enemies!
Beat the kings guard! Now you have a map to continue your journey!
Crushed the evil witch sisters!
Defeated the evil tree!
Defeated the zombie boar!
Defeated the heart of the eel!
Defeated a mutated Max!
Defeated the fart troll!
Defeated Undead Nuburu!
Defeat giant toy rabbit!
Fritzy eats the wizards head!
Defeat the evil sorceress!
You've killed 1000 enemies!
You've killed 2500 enemies!
You've collected 5000 gold pieces.
You've collected 20000 gold pieces.
You've collected 100,000 gold pieces.
You've released your first spirit from it's shackles!
You've released 15 spirits!
You've released all spirits!
Found your first Doll!
You've found half the dolls!
You've found all of the dolls!
You've unlocked the hidden level!
You've defeated the Crab Mini boss!
You've completed Stitch Bot!
Collected all of the runes for Fritzy to unlock the gates to the ruins!
Finished Arcade Mode!
Collect the Maddi doll, you've got your face in a game Maddi!