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.
Completed "The Last Samurai."
Destroyed all the Revenant contraptions on "The Last Samurai."
Completed "Resentment Unleashed."
Defeated the Onmoraki during "Resentment Unleashed."
Completed "The Sanada's Resolve."
Completed "Scion of Virtue."
Defeated all of Sanada's Ten Braves in "Scion of Virtue."
Became Ryunoshin the dung lover's best friend.
Collected all Kodama from the Kyushu Region to the Omi Region.
Acquired mystic art for the axe.
Bathed in every hot spring from the Kyushu Region to the Omi Region.
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 Kodama in the Tohoku region.
Bathed in every hot spring in the Tohoku region.
Completed "Spirit Stone Huntress."
Completed "The One-Eyed Dragon's Castle."
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 "Yokai Country."
Acquired mystic art for the odachi.
Completed any mission while transformed into a woman.
Acquired mystic art for the kusarigama.
Defeated the Nue of Mount Hiei.
Made two circuits around Japan.
Completed "The Queen's Eyes."
Defeated Derrick the Executioner.
Acquired mystic art for the tonfa.
Acquired mystic art for Ninjutsu.
Completed "The Demon King Revealed."
Obtained first divine item.
Reached level 100.
Completed "The Samurai from Sawayama."
Completed "The Source of Evil."
Acquired 40 gestures.
Witnessed Tokugawa's forces head toward a decisive battle.
Met with Tokugawa Ieyasu.
Found Muramasa and brought him in.
Reached maximum proficiency with your first weapon.
Used a disguise.
Used the mask of an ugly fellow to defeat an enemy.
Changed your hair style or beard.
Completed "The Demon of Mount Hiei."
Communicated with a yokai 10 times.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Forged an item.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Changed the appearance of an item.
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
Completed your first Twilight mission.
Confused an enemy for the first time.
Completed "Deep in the Shadows."
Bathed in first hot spring.
Reached level 10.
Completed "The Man with the Guardian Spirit".
You have unlocked all achievements!
Acquired mystic art for the sword.
Acquired mystic art for the dual swords.
Acquired mystic art for the spear.
Acquired mystic art for Onmyo Magic.
Made a total of 60 requests at the blacksmith.
Collected all the best materials.
Defeated all types of yokai.
Collected all Guardian Spirits.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Bathed in every hot spring 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.)
Completed "The Sparrow Flies Again."
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Collected all Kodama in the "Siege of Osaka (Summer)" chapter.
Completed "The Grand Tournament" on Way of the Strong or higher.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed the 20th plane in The Abyss.
Destroyed all the destructible cannons in "The Sanada's Resolve."