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