Here is the full list of all 13 A Pretty Odd Bunny achievements.
Find your first Bacon Coin
Eat your first pig.
Collect 11 Bacon Coins in Bunny Town
Get all the bacon on Extra Level #1
Get all the Bacon Coins in Bunny Town
Get all the bacon on Extra Level #2
Get the secret Bacon Coin on Level 1-25
Survive an encounter with The Butcher
Find at least one secret room on The Underground
Get 10 Bacon Coins on The Underground
Get all the bacon on Extra Level #3
Get all the Bacon Coins on The Underground
Visit Piggy Island.