Here is the full list of all 12 Haunt achievements worth 200 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox 360.
Complete the game
Complete the game without using a Vitality Vial
Retrieve the Phantaflask from the Auditory Annex and return it to the statue
Collect every newspaper clipping
Answer the ringing telephone
Defeat one of each type of ghost
Star in a motion picture
Pose for a photo and then admire the picture
Retrieve the Phantaflask from the Luminarium and return it to the statue
Successfully avoid 5 Charger ghost attacks
Retrieve the Phantaflask from the Motility Vaults and return it to the statue
Retrieve the first Phantaflask and return it to the statue