Here is the full list of all 19 Juju achievements.
Complete a level in co-op.
Complete all unlockable levels.
Gather every Coin in the game.
Find all secret teleports.
Defeat Calypso.
Defeat Cobos and collect his key part.
Unlock all skills.
Defeat Octobos and collect his key part.
Make 4 enemies dance at once.
Complete one unlockable level.
Defeat Robos and collect his key part.
Complete any level without losing a heart.
Complete any level without collecting an amber.
Hit 3 enemies with one dash.
Defeat Frobos and collect his key part.
Unlock a new skill.
Collect more than 100% of ambers in any level.
Find a secret teleport.
Gather all Coins on one level.