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