Here is the full list of all 31 Rhythm Sprout: Sick Beats & Bad Sweets achievements.
Finish the Side Story.
Defeat Mrs. Chili.
Defeat The Power Peppers.
Your love of trap doors knows no bounds.
Answered NO on every question at least once.
Answered YES on every question at least once.
Finish the Main Story.
Get 50 Stars.
Defeat K-FLOW.
Be very interested in Sugar Daddy's story.
"Defeat" King Sugar Daddy.
Clear 10 Levels in Turbo Mode.
Defeat Candy Mama.
Listen to the same loop over and over again.
Clear 5 Levels in Random Mode.
Clear 5 Levels in Mirror Mode.
Get one of the Target Scores in any level (no more, no less).
Defeat Count Arelle.
Hit 20 Trap Notes in one level.
Fall through Count Arelle's trap door.
Wear an unlockable skin for multiple levels.
Rewatched a cutscene multiple times.
Die several times in a row.
Cleared the first level.
Got all achievements in Rhythm Sprout!
Clear All Bonus Levels.
Get 100 Stars.
Get your first CD.
Get 10 CDs.
Get 25 CDs.
Get to the finish line with every unlockable skin.