Here is the full list of all 86 Ato achievements.
Obtain all scrolls
Collect EVERYTHING
Perform the just-frame legendary move
Beat Ato on Accessible Difficulty
Beat Ato on Experienced Difficulty
Defeated Demon
Defeated Archer
Collect all runes
Defeated Berserker
Defeated Leader
Once obtained, Successfuly perform the counter ability on an enemy
Max out your magic meter
Defeated Vagrant
Completed Fatal Arena
Defeated Champ
Defeated Blameless
Collect all coins
Collect a magic bar
Defeated Tiny Warrior
Completed Armor Arena
Defeated Turtle
Defeated Tempest
Defeated Phantom Shin
Completed Throw Arena
Destroy 50 wall crystals
Obtain all talismans
Defeated Monk
Perform the legendary move on an enemy
Defeated Cross Blade
Defeated Warden
Defeated Sentinel
Defeated Deceiver
Defeated Father Statue
Cut 50 stalks of bamboo
Defeated Samurai
Completed Spin Arena
Defeated Daggerman
Defeated Yari
Defeated Child Statue
Defeated Shadow Jin
Warp from one gate to another
Defeated Geisha
Equip a Rune
Obtain your first Rune
Defeated Twins
Hit opponent 5 times while they are launched
Defeated Ancient Warrior
Defeated Mother Statue
Defeated Bandit
Destroy a blue crystal block
Defeated Acolyte
Defeated Ninja
Jump 1000 Times
Defeated Guardian
Obtain your first Coin
Defeated Jin
Parry your opponent
Increase your max health
Obtain your first Talisman
Defeated Rogue
Defeat The Leader without killing his servants
Defeated Warden without the vision upgrade
Beat Ato on Bushido Difficulty
Beat the first 3 bosses on Hell Difficulty
Beat Ato on One Hit Difficulty Mode
Beat Ato without collecting a Rune
Beat Ato without obtaining a dodge ability
Beat Ato without collecting Talismans, Coins, Runes nor extra Magic
Beat Ato in 2 Hours