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 any mission while transformed into a woman.
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Acquired mystic art for Onmyo Magic.
Acquired mystic art for Ninjutsu.
Completed the 20th plane in The Abyss.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Made a total of 60 requests at the blacksmith.
Became Ryunoshin the dung lover's best friend.
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Acquired 40 gestures.
Collected all the best materials.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed "The Grand Tournament" on Way of the Strong or higher.
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
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."
Completed "The Sparrow Flies Again."
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."
Bathed in every hot spring in the "Siege of Osaka (Winter)" chapter.
Acquired mystic art for the tonfa.
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)."
Completed "Hands of the Dragon."
Completed "Spirit Stone Huntress."
Completed "The One-Eyed Dragon's Castle."
Bathed in every hot spring in the Tohoku region.
Collected all Kodama in the Tohoku region.
Listened to Katakura Shigenaga's entire introduction in "The One-Eyed Dragon's Castle."
Acquired mystic art for the odachi.
Completed "Yokai Country."
Acquired mystic art for the kusarigama.
Made two circuits around Japan.
Completed "The Queen's Eyes."
Used the mask of an ugly fellow to defeat an enemy.
Defeated Derrick the Executioner.
Collected all Kodama from the Kyushu Region to the Omi Region.
Communicated with a yokai 10 times.
Acquired mystic art for the axe.
Completed "The Demon King Revealed."
Obtained first divine item.
Acquired mystic art for the dual swords.
Completed "The Samurai from Sawayama."
Reached level 100.
Acquired mystic art for the spear.
Completed "The Source of Evil."
Acquired mystic art for the sword.
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 "The Demon of Mount Hiei."
Defeated the Nue of Mount Hiei.
Used a disguise.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Completed your first Twilight mission.
Changed your hair style or beard.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Confused an enemy for the first time.
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".