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