Here is the full list of all 38 Moss achievements.
Rescue Argus without a single death.
Collect all of the forgotten fragments.
Collect all of the Relic Dust.
Destroy two or more Screecher enemies with a controlled Ticker.
Break everything within the town pub that can be broken.
Find a low-hanging path to the town pub.
Destroy a Forged enemy with a controlled Scorcher.
Light the torches of the Knights of the Sun.
Destroy a Forged enemy with an aerial attack.
Startle Quill from behind.
Finish the first book of Moss.
Defeat the serpent Sarffog.
Climb to the castle bridge alongside Quill.
Collect a large amount of Relic Dust.
Use your power as a Reader to break many objects.
Enter the Abandoned City alongside Quill.
Enter the Namelhook Mining cave alongside Quill.
Take control over many Forged enemies.
Unlock the path to the Mire Temple's altar room.
Collect a small amount of Relic Dust.
Guide Quill to destroy multiple thorn patches.
Give Quill a high five.
Use a Screecher to unlock the path forward.
Annoy Quill by delaying the adventure.
Enter the Mire Temple alongside Quill.
Defeat the Screechers first encountered in the Mire.
Use your power as a Reader to heal Quill for the first time.
Follow the Starthing and Quill into the impassable Mire.
Enter the Clearing alongside Quill.
Discover your first Forgotten Piece.
Use Quill's sword to cut down a lot of grass.