Here is the full list of all 18 Waking Violet achievements.
Complete the first level.
Complete the first block of levels
Complete the first ice level
Replay a level
Complete 15 levels
Complete 30 levels
Kill a monster with a door
Learn all powers
Die outside levels
Use a hint
Reach the final levels
Beat a secret level
Beat both secret levels
Complete five levels without using undo
Complete the game without using hints
Wake up from the dream
Free the alchemist in the real world
Defeat the alchemist once and for all