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