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