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