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 Sarutobi Sasuke in the mission "The Siege of Osaka (Winter)" using only tonfa. (Cannot use a Visitor/Companion.)
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed "The Grand Tournament" on Way of the Strong or higher.
Defeated Ganryu's Sasaki Kojiro using only Dual Wooden Swords. (Cannot use a Visitor/Companion.)
Completed the 20th plane in The Abyss.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Made a total of 60 requests at the blacksmith.
Changed your hair style or beard.
Used all the culverins in the mission "The Siege of Osaka (Winter)."
Bathed in every hot spring in the Tohoku region.
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
Became Ryunoshin the dung lover's best friend.
Used the mask of an ugly fellow to defeat an enemy.
Collected all the best materials.
Acquired mystic art for the tonfa.
Acquired mystic art for the odachi.
Acquired mystic art for the axe.
Acquired mystic art for the spear.
Acquired mystic art for the dual swords.
Listened to Katakura Shigenaga's entire introduction in "The One-Eyed Dragon's Castle."
Confused an enemy for the first time.
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."
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."
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.
Communicated with a yokai 10 times.
Forged an item.
Collected all Kodama in the Tohoku region.
Completed the mission "The Siege of Osaka (Winter)."
Completed "Hands of the Dragon."
Completed "Spirit Stone Huntress."
Completed "The One-Eyed Dragon's Castle."
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Completed "Yokai Country."
Acquired 40 gestures.
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
Completed your first Twilight mission.
Acquired mystic art for the kusarigama.
Completed any mission while transformed into a woman.
Used a disguise.
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 Onmyo Magic.
Acquired mystic art for Ninjutsu.
Reached level 100.
Completed "The Source of Evil."
Acquired mystic art for the sword.
Witnessed Tokugawa's forces head toward a decisive battle.
Changed the appearance of an item.
Found Muramasa and brought him in.
Met with Tokugawa Ieyasu.
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.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Completed "Deep in the Shadows."
Bathed in first hot spring.
Reached level 10.
Completed "The Man with the Guardian Spirit".