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.
Defeat 250 enemies using Shantae's Monster Whipper!
Defeated the Ammo Baron.
Obtain Squid Oil.
Release the Ham Stink.
Obtain all three Mummy Sketches.
Obtain the Golden Pickaxe.
Obtain the Fossil.
Collect the Enchanted Blade.
Obtain Manly Musk.
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.
Defeated the Cyclops Plant without taking damage.
Defeated the Empress Spider.
Defeated the Empress Spider without taking damage.
Defeated the Squid Baron.
Defeated the Squid Baron without taking damage.
Defeated Dagron.
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.
Defeat 50 enemies using Pirate Weapons.
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.
Use a Pirate Flare to return to Risky's ship.
Defeated the Cyclops Plant using only Pike Balls.
Destroy 10 Spider Eggs before they hatch.
Sample the entire menu!