Full list of all 23 Destiny 2 achievements. It takes around 200 hours to unlock all of the achievements in the base game on Windows.
The base game contains 13 achievements, and there is 1 DLC pack containing 10 achievements.
Complete the Leviathan raid.
Complete the Leviathan raid on Prestige difficulty.
Complete 30 challenges.
Collect 15 Red War exotic weapons or armor.
Acquire each Titan subclass.
Acquire each Warlock subclass.
Complete Introduction: Crucible.
Encounter an Agent of the Nine somewhere in the system.
Complete a Flashpoint on Earth, Titan, Nessus, or Io.
Complete a Nightfall strike.
Complete a Heroic public event.
Reach level 20.
Acquire each Hunter subclass.
Complete a Triumph Seal.
Collect 10 Forsaken Exotic weapons or armor.
Complete the "Last Wish" Raid.
Complete a Forsaken Exotic Quest.
Pursue Uldren and the Fanatic to the Watchtower, and finish what you started.
Earn 5,000 Triumph points.
Win a Gambit match.
Defeat a Forsaken Nightfall Boss.
Enter the Dreaming City.
Complete a Collections Badge.