Here is the full list of all 16 Psychoduck achievements.
Hunt 10 snails!
Hunt 30 snails!
Hunt 50 snails!
Kill the heron for the first time!
Kill 10 herons!
Kill 30 herons!
Kill 50 herons!
Push the stone for 200m!
Push the stone for 500m!
Push the stone for 1000m!
Hide in the bush!
Attract a frog to the bush!
Attract two frogs to the bush!
Hitch a ride at the alligator!
Give the turtle an apple!
Beat a game!