Here is the full list of all 44 Shantae and the Pirate's Curse achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Discover the secret Labyrinth.
Defeated the Steel Maggot.
Collect all Labyrinth maps.
Help Ammo Baron fire the Palace Disruptor Cannon.
Obtain the Spirit from Abner.
Defeat 50 enemies using Pirate Weapons.
Collect the Enchanted Blade.
Defeated Dagron.
Obtain Manly Musk.
Use a Pirate Flare to return to Risky's ship.
Obtain the Fossil.
Collect 50% of the Dark Magic.
Sample the entire menu!
Defeated the Squid Baron.
Collect 50% of the Heart Squids.
Obtain the Golden Pickaxe.
Obtain all three Mummy Sketches.
Defeated the Empress Spider.
Destroy 10 Spider Eggs before they hatch.
Obtain Squid Oil.
Defeated the Cyclops Plant.
Defeat 250 enemies using Shantae's Monster Whipper!
Release the Ham Stink.
Defeated the Ammo Baron.
Play keep away with the Ammo Baron.
Defeated the Ammo Baron without taking any damage.
Defeated the Cyclops Plant without taking damage.
Defeated the Empress Spider without taking damage.
Defeated the Squid Baron without taking damage.
Defeated Dagron without taking damage.
Defeated the Steel Maggot without taking damage.
Defeated the Pirate Master.
Defeated the Pirate Master without taking damage.
Saved Scuttle Town as fast as possible!
Defeat the Pirate Master's true form.
Defeat the Pirate Master's true form and save Scuttle Town in record time!
Defeated the Pirate Master's true form without taking any damage.
Complete the game without any Health upgrades and all Heart Squids collected.
Collect all Heart Squids.
Collect all of the Dark Magic.
Get Rottytops to Abner Tree without making any mistakes in a single attempt.
Complete the hidden training room.
Destroy 20 bones with the Bubble Shield.
Defeated the Cyclops Plant using only Pike Balls.