Here is the full list of all 37 Aritana and the Harpy's Feather achievements.
Win the Mountain battle against Mapinguari.
Survive the third encounter without using the Defense Ability.
Lose 3 lifes against Mapinguari in any encounter.
Lose one life in any level.
Complete all the bonus stages.
Reach maximum health.
Win the Cave battle against Mapinguari.
Get fifteen Muiraquitãs.
Jump a great distance using the Agility Boost.
Dodge a Red Spirit and make him fall into the abyss.
Use the Search Ability to find a secret area.
Win the Forest battle against Mapinguari.
Collect 2 Medicial Plants to increase your health.
Fall 3 times into the water during the same level.
Offer five Muiraquitãs at the end of any level.
Bring down a tree.
Avoid getting stunned after a high fall using the Agility Stance.
Get hit by a Spirit right after it's respawn.
Make a combo.
Try to knock out a Spirit jumping over its head.
Get 100 guaranás.
Get one Muiraquitã.
Reach 99 lives.
Survive the first encounter without losing health.
Survive the second encounter without letting any rock hit the ground.
Find 3 combos throughout the game.
Make a combo using the Strenght Boost.
Lose one health point trying to attack a Red Spirit.
Stay in the air for one minute without hitting the ground.
Make 3 different combos without hitting the ground.
Make 100% of the game and see the extended ending.
Get thirty Muiraquitãs.
Get all Muiraquitãs.
Get all the Forest Muiraquitãs.
Get all the Cave Muiraquitãs.
Get all the Mountain Muiraquitãs.
Find all combos.