Here is the full list of all 13 Numberline achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Complete 25 levels
Complete 20 levels
Complete 15 levels
Complete 10 levels
Complete 5 levels
Complete your first level
Complete 30 levels
Complete 35 levels
Complete 40 levels
Complete 45 levels
Complete 50 levels
Complete 55 levels
Complete 60 levels