Here is the full list of all 20 Diamond Joyce and the Secrets of Crystal Cave achievements.
Finish 10th scenario
Finish 9th scenario
Finish 8th scenario
Finish 6th scenario
Finish 200 levels
Finish 7th scenario
Finish 5th scenario
Finish 100 levels
Finish 4th scenario
25 monsters killed
Killed by a monster!
Finish 3rd scenario
Finish 50 levels
Finish 2nd scenario
Collect 100 diamonds
Finish 20 levels
Finish tutorial scenario
1 monster killed
Collect 25 diamonds
Finish first level!