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.
Defeated the Pirate Master.
Defeated the Steel Maggot.
Collect 50% of the Heart Squids.
Help Ammo Baron fire the Palace Disruptor Cannon.
Obtain the Spirit from Abner.
Collect the Enchanted Blade.
Defeat 50 enemies using Pirate Weapons.
Collect 50% of the Dark Magic.
Defeated Dagron.
Obtain Manly Musk.
Obtain the Fossil.
Defeated the Squid Baron.
Sample the entire menu!
Obtain the Golden Pickaxe.
Obtain all three Mummy Sketches.
Use a Pirate Flare to return to Risky's ship.
Defeated the Empress Spider.
Destroy 10 Spider Eggs before they hatch.
Obtain Squid Oil.
Defeat 250 enemies using Shantae's Monster Whipper!
Defeated the Cyclops Plant.
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 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.
Discover the secret Labyrinth.
Complete the hidden training room.
Collect all Labyrinth maps.
Destroy 20 bones with the Bubble Shield.
Defeated the Cyclops Plant using only Pike Balls.