Here is the full list of all 75 Halo Wars: Definitive Edition achievements.
Disrupt 5 active Leader Powers in a single game on Blood River.
Get a Gold Medal on every Campaign Mission.
100% Completion.
Finish all missions under Par Time on Heroic difficulty.
Play Halo Wars for at least 24 Total hours.
Complete the Campaign on Heroic Difficulty.
Complete the Campaign on Legendary Difficulty.
Mission 1: Ram and kill 50 Grunts with Warthogs.
Win 100 Skirmish or Multiplayer Matches.
Finish five missions under Par Time on Heroic difficulty.
Win 75 Skirmish or Multiplayer Matches.
Obtain a lifetime campaign Score over 1,000,000.
Complete any Campaign Mission in Co-op Mode.
Win a Public game.
Win and have the highest score in a Public Game.
Win 50 Skirmish or Multiplayer Matches.
Win a game in every Skirmish Game Mode.
Get a Scarab during a Reinforcement game.
Gain at Least 15 population from a single wave in a Reinforcement game.
Hot drop 50 squads to your Covenant Leader in a single game on Barrens.
Win 40 Skirmish or Multiplayer Matches.
Win 30 Skirmish or Multiplayer Matches
Kill 20 enemy squads with a continuous Covenant Leader Power on Memorial Basin.
Get 20,000 points in any Skirmish Game.
Collect all Skulls.
Mission 4: Save Adam.
Unlock All Timeline Events.
Mission 2: Destroy every Methane Tank.
Completed Mission 15 on any difficulty.
Mission 15: Open the Doors in order.
Win a game on every Skirmish Map.
Win 20 Skirmish or Multiplayer Matches
Improve your Score in any Campaign Mission.
Finish with 5000 net resources tributed to your teammates on Memorial Basin except in Deathmatch.
Win 10 Skirmish or Multiplayer Matches
Completed Mission 14 on any difficulty.
Mission 14: Don't claim an extra base.
Completed Mission 13 on any difficulty.
Mission 13: Destroy 25 units with the Scarab.
Mission 3: Kill at least 5 Covenant Units with the Bridge.
Mission 12: Repair the Power Core in less than 4 minutes.
Get a Gold Medal with all Debuff Skulls Active.
Collect 8 Skulls.
Mission 5: Jack 6 Covenant Vehicles.
Completed Mission 12 on any difficulty.
Completed Mission 11 on any difficulty.
Mission 11: Save all the Airlocks.
Completed Mission 10 on any difficulty.
Mission 10: Distrupt all Tractor Beams.
Completed Mission 9 on any difficulty.
Mission 9: Put every Colony in Hibernation Mode at the same time.
Score the winning point in a game of Keepaway against Legendary AI's.
Win a Skirmish Game with every Leader.
Unlock 20 Timeline Events.
Mission 7: Do not destroy any Power Node.
Use one of the 6 Major Leader Powers to destroy an enemy's last unit.
Completed Mission 8 on any difficulty.
Mission 8: Use Elephants to train 100 infantry.
Completed Mission 7 on any difficulty.
Mission 6: Successfully protect every Rhino.
Completed Mission 6 on any difficulty.
Collect your first Skull.
Get a Gold Medal on any mission.
Completed Mission 5 on any difficulty.
Completed Mission 4 on any difficulty.
Win a 3v3 Skirmish game with 2 AI Allies.
Win and never trail in a Tug of War game.
Win a Heroic Skirmish Game against the AI in under 10 minutes.
Get a winning High Score with 10 or less Squads against the Heroic AI.
Win a Skirmish Game with Dual Scarabs.
Unlock a Timeline Event.
Finish one mission under Par Time on Heroic difficulty.
Completed Mission 3 on any difficulty.
Completed Mission 2 on any difficulty.
Completed Mission 1 on any difficulty.