Here is the full list of all 32 Hell Pie achievements.
Monty Python did it with style, don't know how it's done here
Collect 10000 crystals
Complete dining room side quest
Complete the Light Horns challenge level
Plug in all Wi-Fi sticks
Trigger whale explosion
Collect 5000 crystals
All Munchers freed
Defeat the boss of the Sewers
Complete the Ram Horns challenge level
Collect 1000 crystals
Complete the Sprint Horns challenge level
Smash Nugget against the wall
Buy your first outfit
Collect your first ingredient
Meet Cupid
Meet Chef
Complete the Arm Horns challenge level
Complete the Wing Horns Challenge Level
Defeat Gluttony
Defeat the Hell Pie
Use private insurance
Unlock Nugget Fart
Bring all sexy plants together
Collect everything
Collect all Candymeat
Collect all Lucky Cats
Collect all Unilambs
Get all outfits
Witness a dark ritual
Destroy the crosses in Heaven
Hit 10 humans in the factory