Here is the full list of all 31 The Forest of Doom achievements.
Find the ultimate ending in Medium mode
Find the two halves of the dwarfish hammer
Buy all of Yaztromo's items
Tame a flying beast with music
Get caught in an Ogre's tree trap
Kill a creature who hates 'bwight light'
Successfully use the Net of Entanglement
Fight the iconic Shapechanger!
Help two souls out but be duped each time
Escape Darkwood Forest!
Be unlucky in a 'Test your Luck' roll
Fight a feline foe
Release an Earth Elemental on to the world
Bounce your way out of trouble
Be lucky in a 'Test your Luck' roll
Use an aromatic bulb to ward off a night terror
Win an arm-wrestling contest
Fight a creature that has been darted
Eat a strange fruit
Find all the artwork in The Forest of Doom
Find the ultimate ending in Free Read mode
Ride a strange looking horse
Find your new destiny
Face a barrage of eggshell splinters
Return a brass bell to its owner
Find the ultimate ending in Hardcore mode
Be fired upon by arrows in four different encounters
Find all the painted canvas pieces to unlock alternative cover
Reveal the truth about an individual
Suffer at the hands of lycanthropy
Wield a carrot as a deadly weapon