Here is the full list of all 29 INMOST achievements.
Save the cat from the hunter
Kill all jumpers.
Listen to all the rabbit's comments.
Find all the notes.
Listen to all the Storyteller's tales.
Talk to the cats when their sibling is alive.
Collect all the Pain Crystals.
Complete the castle scene without taking damage.
Complete the fire scene without taking damage.
Complete the swamp scene without taking damage.
Complete the Slime Pit scene without taking damage.
Complete the Snow scene without taking damage.
Kill all enemies as the Knight.
Zero deaths as the wanderer.
Play without collecting any pain.
Gain all the achievements.
Finish the final scene.
Discover what's in the attic.
Discover the fountain.
Talk to the cats when their sibling is dead.
Host a Tea Party!
Get the Cookies.
Enter the mines.
Find the rabbit.
Listen to the Storyteller's first tale.
Defeat the first hunter.
Finish the Old Man Scene
Find a hidden Pain Crystal
Finish the Girl Scene