Here is the full list of all 79 Nioh: Complete Edition achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
You have unlocked all achievements!
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed "The Grand Tournament" on Way of the Strong or higher.
Completed the 20th plane in The Abyss.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Completed "The Last Samurai."
Collected all Guardian Spirits.
Defeated all types of yokai.
Destroyed all the Revenant contraptions on "The Last Samurai."
Collected all Kodama in the "Siege of Osaka (Summer)" chapter.
Made a total of 60 requests at the blacksmith.
Completed "Resentment Unleashed."
Defeated the Onmoraki during "Resentment Unleashed."
Completed any mission while transformed into a woman.
Completed "The Sanada's Resolve."
Destroyed all the destructible cannons in "The Sanada's Resolve."
Completed "The Sparrow Flies Again."
Defeated Ganryu's Sasaki Kojiro using only Dual Wooden Swords. (Cannot use a Visitor/Companion.)
Completed "Hands of the Dragon."
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
Bathed in every hot spring in the "Siege of Osaka (Winter)" chapter.
Completed "Scion of Virtue."
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Defeated all of Sanada's Ten Braves in "Scion of Virtue."
Collected all Kodama from the Kyushu Region to the Omi Region.
Used all the culverins in the mission "The Siege of Osaka (Winter)."
Defeated Sarutobi Sasuke in the mission "The Siege of Osaka (Winter)" using only tonfa. (Cannot use a Visitor/Companion.)
Completed the mission "The Siege of Osaka (Winter)."
Collected all Kodama in the Tohoku region.
Communicated with a yokai 10 times.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
Became Ryunoshin the dung lover's best friend.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Completed "Spirit Stone Huntress."
Collected all the best materials.
Defeated Derrick the Executioner.
Completed "The One-Eyed Dragon's Castle."
Acquired mystic art for the spear.
Bathed in every hot spring in the Tohoku region.
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Listened to Katakura Shigenaga's entire introduction in "The One-Eyed Dragon's Castle."
Acquired mystic art for the tonfa.
Acquired mystic art for Onmyo Magic.
Completed "Yokai Country."
Made two circuits around Japan.
Completed "The Queen's Eyes."
Completed "The Demon King Revealed."
Obtained first divine item.
Acquired mystic art for the kusarigama.
Acquired mystic art for Ninjutsu.
Acquired mystic art for the axe.
Completed "The Samurai from Sawayama."
Reached level 100.
Acquired mystic art for the odachi.
Reached maximum proficiency with your first weapon.
Completed "The Source of Evil."
Acquired mystic art for the dual swords.
Used the mask of an ugly fellow to defeat an enemy.
Acquired 40 gestures.
Acquired mystic art for the sword.
Witnessed Tokugawa's forces head toward a decisive battle.
Found Muramasa and brought him in.
Used a disguise.
Met with Tokugawa Ieyasu.
Changed the appearance of an item.
Completed your first Twilight mission.
Changed your hair style or beard.
Completed "The Demon of Mount Hiei."
Defeated the Nue of Mount Hiei.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Confused an enemy for the first time.
Bathed in first hot spring.
Completed "Deep in the Shadows."
Forged an item.
Reached level 10.
Completed "The Man with the Guardian Spirit".