Here is the full list of all 12 Fe achievements.
Learn to climb trees
Find your first Silent Helmet
Gather 10 or more lizards for a conversation
Jump between 10 different trees without touching the ground
Complete the game
Unlock all abilities
Find all Silent Helmets
Lead a bear to a Silent camp
Jump from one owl's back to another
Glide from the top of the waterfall all the way to the marsh
Find all the Fe playing hide & seek
Free an old friend