Here is the full list of all 12 Nonogram Animal Griddlers achievements.
Finished a puzzle
Completed Pack 1
Completed Pack 2
Completed Pack 3
Completed Pack 4
Completed Pack 5
Completed Pack 6
Completed all levels
Complete a 20x20 puzzle from pack 6
Play for 1 hour
Play for 2 hours
Play for 3hours