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 the Onmoraki during "Resentment Unleashed."
Used the mask of an ugly fellow to defeat an enemy.
Became Ryunoshin the dung lover's best friend.
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.)
Made a total of 60 requests at the blacksmith.
Completed "The Grand Tournament" on Way of the Strong or higher.
Communicated with a yokai 10 times.
Used all the culverins in the mission "The Siege of Osaka (Winter)."
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Collected all the best materials.
Defeated Derrick the Executioner.
Completed "The Master Ninja" 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.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Completed "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."
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 any mission while transformed into a woman.
Used a disguise.
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)."
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."
Completed "Yokai Country."
Acquired mystic art for the odachi.
Collected all Kodama from the Kyushu Region to the Omi Region.
Made two circuits around Japan.
Completed "The Queen's Eyes."
Acquired mystic art for the axe.
Acquired mystic art for the spear.
Completed "The Demon King Revealed."
Obtained first divine item.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
Acquired mystic art for the kusarigama.
Acquired mystic art for Ninjutsu.
Acquired mystic art for the dual swords.
Completed "The Samurai from Sawayama."
Acquired 40 gestures.
Acquired mystic art for Onmyo Magic.
Acquired mystic art for the tonfa.
Completed "The Source of Evil."
Reached level 100.
Acquired mystic art for the sword.
Witnessed Tokugawa's forces head toward a decisive battle.
Changed your hair style or beard.
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.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Confused an enemy for the first time.
Lit all three evil-warding bonfires in Itsukushima.
Changed the appearance of an item.
Completed "The Ocean Roars Again."
Completed your first Twilight mission.
Forged an item.
Completed "Deep in the Shadows."
Bathed in first hot spring.
Reached level 10.
Completed "The Man with the Guardian Spirit".