Here is the full list of all 23 The Purring Quest achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Play the piano game with less than 3 mistakes
Collect 200 fishbones in Level 4
Collect 1000 fishbones
Collect 200 fishbones in Level 5
Free all the caged cats
Free Snicker
Find Nala's cup
Find Nora's score
Free Abb
Collect 200 fishbones in Level 3
Free Sheldon
Find Cooper's book
Throw 5 rats into the graveyard holes
Hit dogs 10 times
Break 10 vases
Collect 200 fishbones in Level 2
Free Daisy
Jump over chihuahuas 10 times
Find Oskar's ties
Throw 20 apples
Collect 200 fishbones in Level 1
Find Henri's book
Free Tonks