Here is the full list of all 27 FOG achievements.
The base game contains 0 achievements, and there is 1 DLC pack containing 27 achievements.
ESCAPED HELL
ESCAPED THE 9TH CIRCLE
ESCAPED THE 8TH CIRCLE
ESCAPED THE 7TH CIRCLE
ESCAPED THE 6TH CIRCLE
ESCAPED THE 5TH CIRCLE
ESCAPED THE 4TH CIRCLE
ESCAPED THE 3RD CIRCLE
ESCAPED THE 2ND CIRCLE
ESCAPED THE 1ST CIRCLE
KILLED SATAN
MINE ORE
GATHERED HERBS
CHOPPED WOOD
CAUGHT A FISH
REFORGED A PIECE OF GEAR
EQUIPED ARMOR AND WEAPONS IN EVERY SLOT
EQUIPED LEGENDARIES IN EVERY SLOT
OWNED EVERY WEAPON
OWNED A LEGENDARY OF EVERY WEAPON
OWNED EVERY OIL
OWNED A LEGENDARY OF EVERY OIL
CHANGED SPELLS IN THE SPELLBOOK
ACHIEVED MAX LEVEL
SUCCESSFULLY COMBINED TWO MATERIALS
BROKE A POT
TALKED TO A TOWNSPERSON