Here is the full list of all 63 ATONE: Heart of the Elder Tree achievements.
Fight your first Arena battle.
Protect the Elder Tree.
Train with Thyon.
Help Dallr tune his lute.
Buldr and Forsetti come to Yri's aid.
Talk Sven from his Blue Vein state.
Save Forsetti from her fate.
Set Eiryn on her own path.
Sometimes sacrifice is necessary to save the world.
It's over. You can go home now.
Goodbye little friend.
This is the end.
Collect all the Magic Mead ingredients.
Drink the Magic Mead.
Obtain Mayweed from Sven.
Find a small peice of Odin's spear
Find the famous tiny shield
Return Eiryn's knife to its rightful owner.
Answer all of Vèldin's questions correctly.
Complete all of Isa's puzzles.
Solve the Grid puzzle.
Solve the Stumped puzzle.
Solve the Stumped Again puzzle.
Solve the Stumped to Death puzzle.
Solve the Jumbled Divide puzzle.
Solve the Jumbled Freedom puzzle.
Solve the How Many? puzzle.
Solve the Who Sits Where? puzzle.
Solve Gulli's Puzzle.
Solve the Griddled puzzle.
Solve the Blockad puzzle.
Solve the Tracked puzzle.
Solve the grouped puzzle.
Solve the Water Runes puzzle.
Solve the Spring puzzle.
Solve The Unsolvable Puzzle.
Solve the Bloodtrack Puzzle.
Aid Blue Heart in her task.
Unlock 13 Battles.
Battle Sven.
Battle Jörm.
Battle Old Man Wulf.
Battle Viktor.
Battle Buldr.
Battle Heldi.
Battle Skullhorn.
Battle the Ice King.
Battle Hati and Skol.
Obtain Odin's Ring from Jörm.
Obtain Jörm's venom.
Battle Taangrisnir.
Battle Loki.
Battle Freya.
Carry 1250 coins.
Score 6500 points against Odin.
Score 6500 points against Dallr.
Get a 90% hit rate against Tanngrisnir in Arena.
Score more than 10,000 points on any battle.
Get a 90% hit rate on any Arena battle.
Get a 90% hit rate on at least 5 arena battles.
Get a 90% hit rate on at least 10 arena battles.
Get a 90% hit rate on at least 15 arena battles.
Read 20 Story Nodes or Books.