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