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!
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
Completed the 20th plane in The Abyss.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Became Ryunoshin the dung lover's best friend.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed "The Grand Tournament" on Way of the Strong or higher.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Changed the appearance of an item.
Collected all Kodama in the "Siege of Osaka (Summer)" chapter.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Collected all Kodama from the Kyushu Region to the Omi Region.
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Defeated Sarutobi Sasuke in the mission "The Siege of Osaka (Winter)" using only tonfa. (Cannot use a Visitor/Companion.)
Defeated Ganryu's Sasaki Kojiro using only Dual Wooden Swords. (Cannot use a Visitor/Companion.)
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."
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 "Hands of the Dragon."
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
Completed the mission "The Siege of Osaka (Winter)."
Used all the culverins in the mission "The Siege of Osaka (Winter)."
Used the mask of an ugly fellow to defeat an enemy.
Collected all the best materials.
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."
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Acquired mystic art for the axe.
Acquired mystic art for the odachi.
Acquired mystic art for Onmyo Magic.
Acquired mystic art for the tonfa.
Acquired mystic art for Ninjutsu.
Acquired mystic art for the spear.
Acquired mystic art for the sword.
Acquired 40 gestures.
Acquired mystic art for the kusarigama.
Completed "Yokai Country."
Made two circuits around Japan.
Completed "The Queen's Eyes."
Defeated Derrick the Executioner.
Completed "The Demon King Revealed."
Obtained first divine item.
Completed "The Samurai from Sawayama."
Reached level 100.
Acquired mystic art for the dual swords.
Completed "The Source of Evil."
Completed any mission while transformed into a woman.
Used a disguise.
Witnessed Tokugawa's forces head toward a decisive battle.
Met with Tokugawa Ieyasu.
Changed your hair style or beard.
Found Muramasa and brought him in.
Reached maximum proficiency with your first weapon.
Communicated with a yokai 10 times.
Completed "The Demon of Mount Hiei."
Defeated the Nue of Mount Hiei.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Confused an enemy for the first time.
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".