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