Here is the full list of all 13 Pixel Art Coloring Book achievements.
Color the entire Food category.
Color the entire Architecture category.
Color the entire Animals category.
Color 10 hard pictures.
Color 10 medium pictures.
Color 10 easy pictures.
Use Bomb 5 times.
Use Magic wand 5 times.
Color 3 pictures without using boosters.
Use Color splash 5 times.
Use Tornado 1 time.
Color your first picture.
Open the game