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