Here is the full list of all 25 Eventide: Slavic Fable achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Finish the additional Story
Save your Grandma
Free the Lilacus
Save the Fern Flower from extinction
Get into the castle
Prepare a magic halter - defeat a flying opponent
Complete one puzzle with less than 5 miss clicks
Find the Oldest Tree in the forest
Cross the lake
Watch all the cutscenes from the first hour of the game
Prepare the healing balm
Finish three minigames in a row without skipping
Extinguish the fire
Finish a minigame in less than 1 minute
Get out of the car crashed on the cliff
Complete any Hidden Object Puzzle without using hints.
Finish any Object Puzzle in less than 1 minute
Find 3 Hidden Objects in 3 seconds
Finish all minigames without skipping
Complete all puzzles without hints
Talk to every creature in the Museum
Finish the game in Expert mode
Read all the notes placed in the game
Find all sparkling flowers hidden on the scenes
Find all secret bestiary cards and know all the creatures