The following are obtained simply by completing the game:

Key of Snakes
Find the Key of Snakes


Key of Stones
Find the Key of Stones


Key of Spirits
Find the Key of Spirits


Ophidiophia
Slay the Queen of Venom


Atlas of Beyond
Discover the Atlas of Beyond


Immortal no more
Find the Shard of Life


Back to reality
Return from the Spirit Mirror

These achievements take a bit of hunting, but I have included an additional guide for some help.

Archaeologist
Find a Relic Fragment


Historian
Complete a Relic


Curator
Complete all Relics


Preservation Society
Break all Vases



https://steamproxy.net/sharedfiles/filedetails/?id=1089028489
Credits: https://steamproxy.net/id/erikae go rate their guide :)

Gathering moss
Get crushed by a Boulder


This will happen naturally unless you flawless the game, so not very difficult to miss.

Into the abyss
Kill a creature by making it fall to its death


Same with this one, should happen through natural progression.

Put this apple on your head
Throw a spear six nodes or farther


This can be done during The Maze of Stones, Level 3. Kill the snake from the farthest distance.

Déjà-vu
Slay the same creature four times in a row


Beginning The Cave of Fire Book, kill an enemy and wait for it to resurrect 3 times.

Getting crafty
Stack two Pillars


Master builder
Stack three Pillars


These can be done at the same time during the The Cave of Fire Book, Level 6. Pull the lever then stand on the button to stack the pillars. Use the path above to move the rest.

Thanks for reading, let me know if this helps! This game was short and sweet, only taking me a few hours to 100%. Hopefully reading this makes it as painless for you as well <3