Here is the full list of all 15 Coloring Game 2 achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Complete image 15
Complete image 14
Complete image 10
Complete image 9
Complete image 6
Complete image 12
Complete image 11
Complete image 13
Complete image 8
Complete image 7
Complete image 5
Complete image 4
Complete image 2
Complete image 3
Complete image 1