Here is the full list of all 40 Shantae and the Seven Sirens achievements.
Avoid startling the Lobster Girl throughout the adventure.
Complete the game without any Health upgrades and all Heart Squids collected.
Complete the adventure with 100% completion as quickly as possible!
Unearthed all secrets.
Complete the adventure as quickly as possible!
Complete the game in Rule Breaker or Full Deck Mode.
Complete the adventure with 100% completion!
Collect all Monster Cards.
Open all Shock Machines.
Complete the adventure!
Complete the game in Beginner or Definitive Mode.
Defeated the Empress Siren.
Deactivate all the Towers.
Defeated the fifth Siren.
Obtain all magical forms.
Shock a circus squid.
Complete a Ghostly Quest.
Upgrade all magic to max.
Witness every magical outcome with Slimes.
Unearth a buried treasure.
Learn all magical dances.
Defeated the fourth Siren.
Revitalize cellular functions.
Locate the sunken ship remains.
Turn an enemy to an ally by helping them heal.
Fell for a double cross.
Open a Shock Machine.
Ascend to Armor Town.
Enter the Sea Lab.
Defeated the third Siren.
Obtain the Lucky Amulet.
Defeated the second Siren.
Use the valve.
Uncovered a possible threat.
Win the highest total in a Hula Contest.
Reach Tree Town.
Have three Monster Cards equipped at once.
Defeated the first Siren.
Took the tour!
Obtain a Monster Card.