Here is the full list of all 52 Lone Fungus achievements.
Achieve 100% completion and finish the game (True Ending)
Learn everything you can from the Grand Librarian
Listen what the Professor Statue has to say about each mushroom cap
Parry 200 Projectiles
Collect all Astral Fragments
Collect all Relics
Use the Bouncy Spore Spell to reach somewhere higher up
Downward Slash the Bouncy Spore 5 times in a row without touching the ground
Collect 75 Mindshrooms
Collect all Emblems
Leave the Kingdom (Abandonment Ending)
Unlock all Bounce abilities
Collect all Ladybugs
Fully upgrade your sword's damage
Open all levered one way gates
Read all the 'Ten Commandments' tablets
Unlock the Teleportation Wand
Collect all Health Crystals
Unlock the Royal Ornament
Cut 1000 Flowers/Flora
Talk to every Major Statue
Collect all Brain Nodes
Acquire the Returning Contraption Spell
Complete the game (True Ending / Selfish Ending)
Fullfill your destiny on the 'Normal' Difficulty (True Ending)
Learn both Great Slashes
Acquire the Spark Ball Spell
Acquire the Vibrant Crystal Spell
Collect 50 Mindshrooms
Collect all Spell Stones
Acquire the Golden Light Spell
Acquire the Berserk Spell
Unlock the Fire Bounce ability
Acquire the Spicy Nut Spell
Acquire the Bouncy Ball Spell
Unlock the Crouch Jump ability
Defeat 500 Enemies
Collect 25 Mindshrooms
Unlock the Spin Jump
Unlock the Wall-Bounce ability
Acquire the Acid Hammer Spell
Collect 4 Health Crystals
Acquire the Boost Projectile Spell
Acquire the Bouncy Spore Spell
Unlock both the Dashes
Defeat 100 Enemies
Learn how to Conjure a Mushmover
Unlock the Mushmover Infusion ability
Fullfill your destiny on the 'Hardcore' Difficulty (True Ending)
Fullfill your destiny on the 'Nightmare' Difficulty (True Ending)
Forget the past, reincarnate only the Greencap culture of mushrooms (Selfish Ending)
Achieve 100% completion and finish the game on the 'Nightmare' Difficulty (True Ending)