Full list of all 67 Assassin's Creed Origins achievements. It takes around 60-80 hours to unlock all of the achievements in the base game on Windows.
The base game contains 53 achievements, and there are 2 DLC packs containing 14 achievements.
Perform a leap of faith from Arsinoe's sundial obelisk between 10 am and noon (The Hidden Ones)
Perform 3 Assassinations from a zipline (The Hidden Ones)
Free 20 Rebels (The Hidden Ones)
Kill an enemy with a headshot while they are being harassed by Senu (The Hidden Ones)
Complete the Walls-of-the-Ruler citadel (The Hidden Ones)
Assasinate Tacito, Ptahmose and Ampelius (The Hidden Ones)
Complete Side DLC Quests "Rise of Shaqilat" and "Shadows of the Scarab" (The Hidden Ones)
Complete Main DLC Quest "The Greater Good" (The Hidden Ones)
Reach level 55 (The Curse of the Pharaohs)
Acquire Eternal Maw for use outside the Afterlifes (The Curse of the Pharaohs)
Complete the 5 Serqet locations (The Curse of the Pharaohs)
Craft an upgrade using Shards of a Star (The Curse of the Pharaohs)
Kill a Mummy by setting it on fire (The Curse of the Pharaohs)