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 Dagron.
Defeat 50 enemies using Pirate Weapons.
Obtain Manly Musk.
Sample the entire menu!
Obtain the Fossil.
Defeated the Squid Baron.
Obtain the Golden Pickaxe.
Obtain all three Mummy Sketches.
Defeated the Empress Spider.
Destroy 10 Spider Eggs before they hatch.
Use a Pirate Flare to return to Risky's ship.
Obtain Squid Oil.
Defeated the Cyclops Plant.
Defeat 250 enemies using Shantae's Monster Whipper!
Release the Ham Stink.
Defeated the Ammo Baron.
Collect the Enchanted Blade.
Obtain the Spirit from Abner.
Play keep away with the Ammo Baron.
Help Ammo Baron fire the Palace Disruptor Cannon.
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.
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 50% of the Heart Squids.
Collect all Heart Squids.
Collect 50% of the Dark Magic.
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.