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 Grand Tournament" on Way of the Strong or higher.
Completed the 20th plane in The Abyss.
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Defeated Ganryu's Sasaki Kojiro using only Dual Wooden Swords. (Cannot use a Visitor/Companion.)
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.)
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Made a total of 60 requests at the blacksmith.
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.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
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."
Collected all Kodama in the "Siege of Osaka (Winter)" 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."
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."
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."
Collected all the best materials.
Became Ryunoshin the dung lover's best friend.
Collected all Kodama in the Tohoku region.
Acquired mystic art for the dual swords.
Acquired mystic art for the axe.
Acquired mystic art for the tonfa.
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."
Acquired mystic art for the odachi.
Completed "Yokai Country."
Acquired mystic art for the sword.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
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.
Completed "The Samurai from Sawayama."
Acquired mystic art for Ninjutsu.
Acquired mystic art for Onmyo Magic.
Acquired mystic art for the spear.
Completed "The Source of Evil."
Reached level 100.
Acquired mystic art for the kusarigama.
Witnessed Tokugawa's forces head toward a decisive battle.
Acquired 40 gestures.
Changed the appearance of an item.
Met with Tokugawa Ieyasu.
Found Muramasa and brought him in.
Changed your hair style or beard.
Reached maximum proficiency with your first weapon.
Completed any mission while transformed into a woman.
Used a disguise.
Completed "The Demon of Mount Hiei."
Defeated the Nue of Mount Hiei.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Confused an enemy for the first time.
Communicated with a yokai 10 times.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Completed your first Twilight mission.
Used the mask of an ugly fellow to defeat an enemy.
Forged an item.
Completed "Deep in the Shadows."
Bathed in first hot spring.
Reached level 10.
Completed "The Man with the Guardian Spirit".