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