Here is the full list of all 9 The Haunting of Billy achievements.
Blow an enemy clean off the level.
Don't take Bucky with you.
Meet your loving and caring guardian demon.
Find your way off the level.
Find and equip Bucky's pan.
Have on you 250 candy at one time.
Wear a full costume set.
Look at that lil' devil!
Wear a full costume where every piece is unique.