Here is the full list of all 29 Watch Your Plastic Duck achievements.
Collect 5 ducks
Collect 25 ducks
Collect 50 ducks
I want to believe
Mass extinction
Call the priest!
And the sky is gray
Witness the rainbow duck
Especiallly dragon fire
Thaw out a prehistoric duck
Watch ducks for 5 hours straight
Click various objects 5 times
Click various objects 50 times
Click various objects 500 times
Click various objects 5000 times
Touch the pumpkin
Use easel and change duck
Touch the gift
Get a glitchy duck
Get duck level 5
Get duck level 10
Get duck level 20
Get a duck with any stat equal to 10
Get a duck with any stat equal to 20
Get a duck with all stats from 10
Get a duck with all stats from 20
Get a duck that drowned 1 duck
Get a duck that drowns 5 ducks
Get a duck that drowns 10 ducks