Here is the full list of all 21 Little Dog achievements.
Collect 40 bones
Click on "Menu"
Click on "Play"
Click on "Exit"
Die 30 times from bat
Reach level 12
Reach level 11
Die 30 times from cliffs
Reach level 10
Reach level 9
Die 25 times from plants
Reach level 8
Reach level 7
Reach level 6
To be at level 5 for more than three minutes
Jump 100 times
Reach level 5
Reach level 4
Reach level 3
Reach level 2
First level started