Here is the full list of all 20 NecroWorm achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Eat 30 brains
Eat 20 skulls
Complete any level under 5 sec
Earn 10 points
Complete first bonus level
Complete first level
Complete 20 levels
Complete 40 levels
Complete 60 levels
Complete 80 levels
Complete 120 levels
Earn 30 points
Earn 60 points
Earn 100 points
Earn 150 points
Earn 200 points
Earn 300 points
Earn 350 points
Eat 40 eyes
Complete game