Here is the full list of all 22 Boo Party achievements.
Get the Vampire's photo
Get the Demon's photo
Get the Bakeneko's photo
Get the Mummy's photo
Get the Mermaid's photo
Get Medusa's photo
Get the Plant Lady's photo
Get Frankie's photo
Get the Werewolf's photo
Get the Aliens' photo
Get the Slasher's photo
Get the Witch's photo
Get the Scientist's photo
Complete Succu-Bouncer in single-player
Get the secret photo
Pet all the cats
Jump 100 hurdles!
Complete the Cherry Run
Collect 120 Sewer Diamonds
Complete a dance without missing a step
Clear the game
Complete Time Attack in less than 60 minutes