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