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