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 Grand Tournament" on Way of the Strong or higher.
Became Ryunoshin the dung lover's best friend.
Bathed in every hot spring in the "Siege of Osaka (Summer)" chapter.
Made a total of 60 requests at the blacksmith.
Completed "The Master Ninja" on Way of the Strong or higher.
Completed "The Sparrow Flies Again."
Completed "Hands of the Dragon."
Completed "Scion of Virtue."
Defeated all of Sanada's Ten Braves in "Scion of Virtue."
Completed "The Last Samurai."
Destroyed all the Revenant contraptions on "The Last Samurai."
Completed "The Sanada's Resolve."
Completed 10 missions with NPC or in the “Yokai Realm with a companion” with other users.
Completed "Resentment Unleashed."
Bathed in every hot spring in the "Siege of Osaka (Winter)" chapter.
Bathed in every hot spring in the Tohoku region.
Defeated the Onmoraki during "Resentment Unleashed."
Defeated all types of yokai.
Used a disguise.
Acquired mystic art for Onmyo Magic.
Acquired mystic art for Ninjutsu.
Acquired mystic art for the tonfa.
Acquired mystic art for the kusarigama.
Acquired mystic art for the axe.
Acquired mystic art for the spear.
Acquired mystic art for the sword.
Acquired mystic art for the dual swords.
Acquired 40 gestures.
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)."
Used all the culverins in the mission "The Siege of Osaka (Winter)."
Completed "Spirit Stone Huntress."
Completed "The One-Eyed Dragon's Castle."
Collected all Kodama in the Tohoku region.
Seized all of Aoba Castle's three-storied keeps in "The One-Eyed Dragon's Castle."
Listened to Katakura Shigenaga's entire introduction in "The One-Eyed Dragon's Castle."
Completed "Yokai Country."
Communicated with a yokai 10 times.
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 your first Twilight mission.
Completed "The Demon King Revealed."
Obtained first divine item.
Collected all Kodama from the Kyushu Region to the Omi Region.
Reached level 100.
Completed "The Samurai from Sawayama."
Acquired mystic art for the odachi.
Completed "The Source of Evil."
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.
Completed "The Demon of Mount Hiei."
Defeated the Nue of Mount Hiei.
Collected all fragments of the Hiragumo teakettle from Shigisan.
Changed your hair style or beard.
Forged an item.
Completed "The Ocean Roars Again."
Lit all three evil-warding bonfires in Itsukushima.
Changed the appearance of an item.
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!
Collected all the best materials.
Collected all Guardian Spirits.
Used the mask of an ugly fellow to defeat an enemy.
Equipped +15 divine equipment in all slots. (Excludes accessories.)
Completed any mission while transformed into a woman.
Collected all Kodama in the "Siege of Osaka (Winter)" chapter.
Defeated Ganryu's Sasaki Kojiro using only Dual Wooden Swords. (Cannot use a Visitor/Companion.)
Equipped the Kusanagi Tsurugi, Yasakani Magatama, and Yata Mirror.
Collected all Kodama in the "Siege of Osaka (Summer)" chapter.
Completed the 20th plane in The Abyss.
Destroyed all the destructible cannons in "The Sanada's Resolve."