Here is the full list of all 40 FEIST achievements.
Complete level 1 «after a long night» without dying
Free yourself from the crate in under a minute
Catch a fly in mid-air
Free your mate
Grab a beast's fur, hold tight, and take it for a ride
Parry a sting projectile
Find a pine in the mine
Don't get hit by a dart trap before the cave
Use all burs by the river
Roll a boulder over a fly
Defeat the teleporting beast with a fly
Defeat a beast with a stick
Provoke an inchworm to hit another
Lure 10 ticks into a fenlight
Avoid all the pit traps
Defeat all beasts
Complete a chapter without eating a midge
Escape the collapsing mine without being crushed
Don't get squashed by a hanging weight
Defeat the three beasts in the ruins without the use of traps
Die during the quake after defeating a beast
Complete level 1 «after a long night» in under 2m 30s
Complete level 2 «a picnic» in under 2m 10s
Complete level 3 «tools of the woods» in under 4m 00
Complete level 4 «down by the lake» in under 3m 45s
Complete level 5 «a bad hair day» in under 4m 50s
Complete level 6 «dwellers in the dark» in under 4m 00s
Complete level 7 «trespassing» in under 4m 10s
Complete level 8 «all good comes from above» in under 1m 45s
Complete level 9 «ruins of the past» in under 4m 30s
Complete level 10 «playing with fire» in under 3m 30s
Complete level 2 «a picnic» without dying
Complete level 3 «tools of the woods» without dying
Complete level 4 «down by the lake» without dying
Complete level 5 «a bad hair day» without dying
Complete level 6 «dwellers in the dark» without dying
Complete level 7 «trespassing» without dying
Complete level 8 «all good comes from above» without dying
Complete level 9 «ruins of the past» without dying
Complete level 10 «playing with fire» without dying