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