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