Here is the full list of all 75 Halo Wars: Definitive Edition achievements worth 1,500 gamerscore.
Got a Gold Medal on every Campaign Mission.
100% Completion.
Won a Public game.
Won and had the highest score in a Public Game.
Won 50 Skirmish or Multiplayer Matches.
Scored the winning point in a game of Keepaway against Legendary AI's.
Won 40 Skirmish or Multiplayer Matches.
Won 30 Skirmish or Multiplayer Matches
Unlocked All Timeline Events.
Won a Skirmish Game with every Leader.
Won a game on every Skirmish Map.
Won 20 Skirmish or Multiplayer Matches
Disrupted 5 active Leader Powers in a single game on Blood River.
Killed 20 enemy squads with a continuous Covenant Leader Power on Memorial Basin.
Hot dropped 50 squads to your Covenant Leader in a single game on Barrens.
Finished with 5000 net resources tributed to your teammates on Memorial Basin except in Deathmatch.
Won and never trailed in a Tug of War game.
Got a winning High Score with 10 or less Squads against the Heroic AI.
Got 20,000 points in any Skirmish Game.
Finished all missions under Par Time on Heroic difficulty.
Completed the Campaign on Heroic Difficulty.
Played Halo Wars for at least 24 Total hours.
Obtained a lifetime campaign Score over 1,000,000.
Used one of the 6 Major Leader Powers to destroy an enemy's last unit.
Finished five missions under Par Time on Heroic difficulty.
Got a Scarab during a Reinforcement game.
Won a game in every Skirmish Game Mode.
Won a Heroic Skirmish Game against the AI in under 10 minutes.
Mission 15: Opened the Doors in order.
Mission 14: Didn't claim an extra base.
Mission 12: Repaired the Power Core in less than 4 minutes.
Mission 7: Did not destroy any Power Node.
Mission 6: Successfully protected every Rhino.
Mission 5: Jacked 6 Covenant Vehicles.
Got a Gold Medal with all Debuff Skulls Active.
Finished one mission under Par Time on Heroic difficulty.
Collected all Skulls.
Mission 1: Rammed and killed 50 Grunts with Warthogs.
Mission 11: Saved all the Airlocks.
Improved your Score in any Campaign Mission.
Mission 9: Every Colony put in Hibernation Mode at the same time.
Mission 8: Used Elephants to train 100 infantry.
Collected 8 Skulls.
Unlock 20 Timeline Events.
Mission 2: Destroyed every Methane Tank.
Mission 4: Saved Adam.
Mission 3: Killed at least 5 Covenant Units with the Bridge.
Completed Mission 15 on any difficulty.
Completed Mission 14 on any difficulty.
Completed Mission 13 on any difficulty.
Mission 13: Destroyed 25 units with the Scarab.
Won 10 Skirmish or Multiplayer Matches
Completed Mission 12 on any difficulty.
Gained at Least 15 population from a single wave in a Reinforcement game.
Completed Mission 11 on any difficulty.
Completed Mission 10 on any difficulty.
Mission 10: Distrupted all Tractor Beams.
Completed Mission 9 on any difficulty.
Completed Mission 8 on any difficulty.
Completed Mission 7 on any difficulty.
Won a Skirmish Game with Dual Scarabs.
Completed Mission 6 on any difficulty.
Completed Mission 5 on any difficulty.
Completed Mission 4 on any difficulty.
Won a 3v3 Skirmish game with 2 AI Allies.
Completed Mission 3 on any difficulty.
Completed Mission 2 on any difficulty.
Collected your first Skull.
Got a Gold Medal on any mission.
Completed Mission 1 on any difficulty.
Unlocked a Timeline Event.
Complete the Campaign on Legendary Difficulty.
Complete any Campaign Mission in Co-op Mode.
Win 100 Skirmish or Multiplayer Matches.
Win 75 Skirmish or Multiplayer Matches.