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