Here is the full list of all 22 Ever Seen A Cat? achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Find 1000 cats from any place.
Got all the achievements!
Find all the individual cats in the abstract place.
Find all the individual cats in candyland.
Find all the individual cats in the park.
Find all the individual cats in the field.
Find all the individual cats in the home.
Find 500 cats from any place.
Find all the individual cats in the galaxy.
Find all the individual cats in the town.
Find all the individual cats in the forest.
Find all the individual cats in the garden.
Cleared all places one time.
Cleared candyland for the first time.
Cleared the park for the first time.
Cleared the field for the first time.
Cleared the home for the first time.
Cleared the galaxy for the first time.
Cleared the town for the first time.
Find 100 cats from any place.
Cleared the forest for the first time.
Cleared the garden for the first time.