Here is the full list of all 21 Meow'n'Dash achievements.
Unlock Murky the kitten
Unlock Frosty the kitten
Unlock Cheeto the kitten
Unlock Inky the kitten
Unlock Elvira the kitten
Unlock Caspar the kitty
Unlock Giskard the RoboCat
Eat 42 crunchy fishies
Make 777x Dash
Hit the wall during the Dash move 100x
Hit the Snowman during the Dash move 100x
Catch 77 Moles
Recolor 999 Yarn Balls
Collect 999 coins
Catch 77 Crows
Recolor 3K Yarn Balls
Recolor 5K Yarn Balls
Recolor 10K Yarn Balls
Hit the Piggy during the Dash move 100x
Hit the Tire during the Dash move 100x
Find the Secret Treasure