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