Here is the full list of all 26 A Walk With My Dog achievements.
Find all photos
Keeps the doctor away
Find the buried treasure
Walk 10,000 steps
It looks like my dog
You finished the walk
You lost the dog but then you found it again
You put the pieces back together
Picked some tasty mushrooms
Can I call him Pepe?
Why did you touch it?
Hit all the lillypads
You found some photos
You let the dog enjoy the squeaky toy
You heard the bell at the church
Have you ever questioned the nature of your reality?
Play tug for at least 20 seconds
You caught three types of animals
You scared a big bird flock 4 times
Made the dog quite happy
Collect three special balls
Took the plastic trash back home
You got a good score on the game console
You took him back home to the garden
You solved all the puzzles
You "fought" the snowman