Here is the full list of all 39 Little Kitty, Big City achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Enjoy 5 cardboard boxes
Drop a phone into the portapotty
Chase a human with a dangerous item
Recycle 100 items
Use your noggin on the soda machine
Knock a human over by jumping on them
Open all Tanuki's portals
Break 100 objects
Score every soccer goal
Find 200 Shinies
Remove all the chess pieces from the board
Bring bones to all the dogs
Meet all the animals
Get photographed 20 times
Put 4 rubber ducks in the pond
Sleep in all the cozy nap spots
Collect all the ducklings
Investigate 10 trash cans
Eat all the yummy fish
Splash paint on the fancy car
This must be how Gecku feels all the time! Raaaaaaaah!
Take 20 photos with your camera
Catch (and release!) 20 birds
Get your very own camera
Leave your pawprints in the wet concrete
Get petted 10 times
Get your first yummy fish
Make 20 humans stumble
Capture a bird in flight
Get a human to kick a ball to you
Meow 10 times in a row
Use an emote
Get kicked out of a store
Smash 10 items
Find your way back home
Collect all the hats
Bust all the old birds' nests
Complete all items on your To-Do list
Make a human slip on a banana