Here is the full list of all 12 Droplitz achievements.
Unlock all themes
Stack 3 Chain Reactions
Collect 5 Droplitz with no path
Use all Droppers and Collectors
Create 40 paths
Unlock all boards in all modes
Survive for 2 hours
Create a multiplier of 50 or more
Score 1,000,000 points
Create a multiplier of 35 or more
Score 250,000 points
Survive for 20 minutes