Here is the full list of all 39 Rainbow Billy: The Curse of the Leviathan achievements.
Break the Curse of the Leviathan and save the World.
Talk to all Kickstarter Backers characters!
Raise ALL creatures' friendships to Level 3!
Befriend all creatures.
Hear each and every one of the The Confessor's secrets.
Get reprimanded for punching barrel-kind.
Accept your other self and befriend Shadow Billy.
Climb to the highest point in each area of the World.
Raise 40 creatures' friendships to Level 3!
Catch at least one of each kind of fish!
Peek through the window...
Raise 30 creatures' friendships to Level 2!
Collect ALL Thought Upgrades!
Collect 75 Thoughts.
Glide using the Billy-Copter for more than 5 straight seconds!
Raise 20 creatures' friendships to Level 3!
Own 500 coins or more.
Discover Disco Broccoli!
Collect 50 Thoughts.
Fast travel between two distant areas of the World.
Face your fears and befriend Calypso.
Collect 25 Thoughts.
Discover the broken warp pipe.
Catch 10 non-gummi items while fishing.
Fight toxic masculinity and befriend Dragalant.
Flawlessly complete a difficult "Dodge" attack minigame!
Flawlessly complete 50 attack minigames!
Raise 5 creatures' friendships to Level 2!
Dig up 15 buried treasures.
Collect 10 Thoughts.
Flawlessly complete a difficult "Paddle" attack minigame!
Recolor five colors in one blow!
Flawlessly complete a difficult "Circle" attack minigame!
Flawlessly complete a difficult "Line" attack minigame!
Flawlessly complete a difficult "Slots" attack minigame!
Destroy 25 Objects!
Catch three different objects in one fishing session!
Convert a Thought into a Figment of Imagination!Service.
Listen to Friend-Ship whistle for more than 5 straight seconds.