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