Here is the full list of all 20 Adventures of Megara: Demeter's Cat-astrophe achievements.
Get all the achievements.
Catch Amalthea on the first try.
Complete all the levels at 3 stars each.
Complete the super bonus level at 3 stars.
Complete all the bonus levels.
Attack the shell 5 times.
Complete the level in difficult mode in Gold time.
Complete 2 bonus levels at 3 stars each.
Collect 10 treasure chests.
Complete 30 levels at 3 stars each.
Do 10 additional tasks.
Collect 5 treasure chests.
Use any ability 10 times.
Complete 15 levels at 3 stars each.
Put together the jigsaw puzzle.
Complete the bonus level without using abilities.
Get 5 achievements.
Complete the level without getting into the wizard's trap.
Find 5 hidden objects.
Send 3 or more characters for work.