Full list of all 73 Halo 5: Guardians achievements worth 1,250 gamerscore. It takes around 40-50 hours to unlock all of the achievements in the base game.
The base game contains 65 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 8 achievements worth 250 Gamerscore.
Called in a REQ that costs 5 Energy or more.
Killed a Legendary Boss in Warzone.
Opened a Gold REQ Pack.
Simultaneously killed two Wardens in The Breaking on Heroic difficulty.
Completed Glassed without any players using Smart-Link.
Completed The Breaking on Legendary difficulty without the entire fireteam dying.
Completed every Mission of the game on Normal difficulty.
Completed every Mission of the game on Heroic difficulty.
Completed every co-op Mission on Heroic difficulty.
Completed Mission 15.
Used a Ground Pound on an exterior power core in Guardians on Heroic difficulty.
Completed Mission 14.
Completed Mission 13.
Operated four different vehicles at once in Mission 13 on Heroic difficulty.
Completed Mission 12.
Knocked two Hunters into the ocean during the Battle of Sunaion.
Killed a Grunt and smashed a grate with a Ground Pound in Battle of Sunaion.
Completed Mission 11.
Escaped the doomed Kraken by jumping onto a Phaeton piloted by a Spartan.
Completed Mission 10.
Completed Enemy Lines without destroying a Kraken turret.
Completed Mission 9.
Completed Mission 8.
Completed Swords of Sanghelios co-op with both Mantises on Heroic difficulty.
Completed Mission 7.
Traversed the canyon without a Phaeton in Reunion on Heroic difficulty.
Completed Mission 6.
Finished Evacuation within 18:00 without dying on Heroic difficulty.
Kept 6 miners alive at the elevator in Evacuation on Heroic difficulty.
Completed Mission 5.
Teamed up in a vehicle to kill 30 enemies in Unconfirmed co-op.
Killed an enemy that's had its armor repaired in Unconfirmed.
Completed Mission 4.
Completed Glassed without entering a vehicle.
Completed Mission 3.
Completed Mission 2.
Escaped the Hunters in the lab and fought them in the hangar in Blue Team.
Simultaneously assassinated two Elites in Blue Team co-op.
Completed Mission 1.
Completed any co-op Mission on Heroic difficulty.
Completed any Mission with 3+ Skulls active on Heroic difficulty.
Helped the Elite General charge the hill in Osiris on Heroic difficulty.
Found and claimed a Skull.
Commanded your team of Spartans in Osiris.
Found and claimed one piece of Intel.
Changed your Emblem in the Spartan Hub.
Changed your Service Tag in the Spartan Hub.
Change your Spartan's gear in the Spartan Hub.
Create and save a Custom Game.
Spectate a game.
Complete 3 matchmade games of Warzone.
Win a match on all three original Warzone maps.
Complete 5 matchmade games of Strongholds.
Complete 5 matchmade games of Breakout.
Complete 5 matchmade games of Capture the Flag.
Complete 5 matchmade games of Slayer.
Complete every Mission of the game on Legendary difficulty.
Find and claim all Intel.
Find and claim all Skulls.
Destroy the Phantom at the Covenant camp in Reunion on Heroic difficulty.
Destroy 10 walls or floors in Swords of Sanghelios.
Finish the 13th mission without losing the Scorpion on Legendary difficulty.
Simultaneously destroy 2 cores in Guardians on Heroic difficulty.
Complete every Mission of the game by yourself on Legendary difficulty.
Qualify for a Competitive Skill Rating.
Completed a mission in Score Attack with at least 500,000 points.
Completed a mission in Score Attack with at least 10,000 points.
Reached 50,000 points in Score Attack with a Skull multiplier of x2 or higher.
Completed a mission in Score Attack co-op, with all participants scoring at least 200,000 points.
Beat the par time of a mission in Score Attack.
Successfully complete 5 Warzone Firefight matches.
Complete a Warzone Firefight match on 6 unique maps.
Earn a Mythic Boss Takedown in a Warzone Firefight match.