Dawn (10 points):
Completed mission 1 on any difficulty.
Requiem (10 points):
Completed mission 2 on any difficulty.
Forerunner (10 points):
Completed mission 3 on any difficulty.
Infinity (10 points):
Completed mission 4 on any difficulty.
Reclaimer (10 points):
Completed mission 5 on any difficulty.
Shutdown (10 points):
Completed mission 6 on any difficulty.
Composer (10 points):
Completed mission 7 on any difficulty.
Midnight (10 points):
Completed mission 8 on any difficulty.
Wake Up, John (20 points):
Completed the Campaign on Normal or harder.
I Need a Hero (40 points):
Completed the Campaign on Heroic or harder.
The Legend of 117 (70 points):
Completed the Campaign on Legendary difficulty.
Lone Wolf Legend (90 points):
Completed the Campaign solo on Legendary difficulty.
Skullduggery (15 points):
Completed any Campaign mission with 3 or more Skulls on Heroic or harder.
Skulls are unlocked by default to you just need to activate them. It is recommended to attempt this on the first mission with the following skulls on:
Bropocalypse (10 points):
Completed any Campaign mission cooperatively on Heroic or harder.
Contact the Domain (10 points):
Found a Terminal in the Campaign.
Refer to Terminus achievement
Terminus (50 points):
Found all of the Terminals in the Campaign.
There are seven terminals in the game. Refer to the guide's “Other Unlockables” section for more details
Digging up the Past (20 points):
Found and accessed Chief’s record in mission 1.
As soon as the game starts, take the stairs to the left to find a lone terminal underneath.
Digging up the past
Midnight Launch (20 points):
Got significant air in the Warthog at midnight in mission 2.
This can only be unlocked in mission 2 and is time-specific. Take note that you should be the driver of the Warthog and you have to make the jump as soon as your console's time has reached 12AM. If its past 12AM (which is most likely the case), you have to manually set your console's time around 23:50 then load Mission 2.
There are no enemies at the start of the stage so just run until you find a warthog. Drive your warthog and follow the path until you reach a destroyed metal tunnel. Wait for 12AM to strike then rush through it until you make a jump. Doing it correctly should unlock the achievement. If not, repeat the whole process again.
This is my Rifle, This is my Gun (20 points):
Carried a UNSC weapon all the way through mission 3 on Heroic or harder.
You'll start off with an Assault Rifle and Magnum Pistol. Choose which one to replace and keep the other one at ALL times, even if it runs out of ammo. In case you accidentally dropped it, revert to your last save and start over again.
Bros to the Close (20 points):
Completed mission 4 without one preventable Marine death on Heroic or harder.
(Rally Point Bravo) It is recommended to play this in co-op as it will be easier to get the aggro and keep the fire away from your allied soldiers. Two marines will join you after encountering Laskey, and four more will be fighting the forerunners in the hill. There are turrets near the door where Cortana will take time to unlock. Use it to keep the enemies at bay at prevent unnecessary marine death.
Mortardom (20 points):
Hijacked a Wraith and used it to kill at least four enemy Wraiths in mission 5 on Heroic or harder.
You need a Plasma Pistol for it's secondary ability – the EMP shot. Disable a wraith by using the Plasma Pistol's charged shot then quickly go its side. There are two options, one is to operate the Plasma Cannon or Operate Wraith. Choose the first then kill the gunner. Next, select Operate Wraith (you may have to disable the vehicle again).
When dealing with Wraiths, keep moving and have a safe distance away from their gunner's cannons. Their main projectiles take them to land and has a predictable arc so don't accidentally move to its landing spot. There are a total of 8 wraiths in the game.
Explore the Floor (20 points):
Tricked or forced a Hunter to fall to his demise in mission 6.
In Rally Point Delta, you'll find two hunters. You must lure one of them into charging you then get out of the way for the last minute so that one of them falls to his death.
Tricked to fall
Give Him the Stick (20 points):
Took out both Hunters using only the Sticky Detonator in mission 7.
If you're going to start Once you've reached the part where there are two Hunters inside the lab, grab a Sticky Detonator from inside the white room or from the left corner of the room. If you're replaying the mission to get this achievement, you can find a Sticky Detonator as soon as you reach the first door. The hunters can be killed with two shots on easy mode.
Give them the stick
Chief, Smash! (20 points):
Killed 3 Crawlers in one hit with the Gravity Hammer in mission 8.
You'll find a gravity hammer along the way, in the armory along side many more weapons. Dig in and survive until more crawlers converge. Time your attack when they're clustered together to get this achievement.
Not Some Recruit Anymore (15 points):
Ranked up your Spartan-IV to SR-5.
Refer to Movin' On Up
Movin’ On Up (25 points):
Ranked up your Spartan-IV to SR-20.
You must earn points and rank up your spartan by playing through the two Infinity game modes (online required)
I <3 Red vs Blue (15 points):
Won 5 War Games matchmaking matches.
Hanging on the Combat Deck (30 points):
Won 20 War Games matchmaking matches.
Operation Completion (15 points):
Completed a Spartan Ops Mission on any difficulty.
A Legendary Episode (40 points):
Completed all chapters in Spartan Ops Episode 1 on Legendary difficulty.
You can't do this with matchmaking since the games are set to Heroic only. You have to do this solo or cooperatively.
Dedicated to Crimson (80 points):
Completed all chapters in the first 5 episodes of Spartan Ops on any difficulty.
Crimson Alone (20 points):
Completed a Spartan Ops chapter solo on Legendary.
Roses vs Violets (20 points):
Found one of the RvB Easter Eggs in Spartan Ops.
No One Left Behind (20 points):
Saved at least one Marine in Chapter 3 of Episode 2 of Spartan Ops on Heroic or harder.
Best attempted cooperatively playing with 4 players. There are 4 marines to protect; just focus fire and prioritize taking out high threat targets first like Elites, Hunters, Ghosts and Wraiths.
Knight in White Assassination (20 points):
Assassinated a Knight in any Spartan Ops mission.
You have to sneak behind a Knight then press RB to assassinate him. You can find one in Infinity EP1, Chapter 4. (Sacred) If he spots you, run away and hide until he gives up and returns to his position. Attempt to sneak and kill him again.
What Power Outage? (20 points):
Completed Chapter 4, Episode 5 of Spartan Ops without losing a generator on Heroic or harder.
No Easy Way Out (20 points):
In Ch 1, Ep 5 of Spartan Ops survived the enemy assault during the defense on Normal or harder.
The Challenged (10 points):
Completed a Challenge.
Refer to “The Challenger”
The Challenger (20 points):
Completed 25 Challenges.
You can check daily, weekly or monthly challenges by accessing them from your Spartan Hub and selecting Career. You can also visit http://www.halowaypoint.com/en-us/intel/challenges for more information.
Armorer (5 points):
Changed your Spartan’s armor in the Spartan Armor card.
Access the Spartan Hub then select Customize > Spartan Armor. Change your any of your armor parts or helmet other than the default Recruit piece.
Badge (5 points):
Changed your Emblem in the Spartan ID card.
Access the Spartan Hub then select Customize > Spartan ID > Emblem. Change your emblem other than the default.
PWND (5 points):
Changed your Service Tag in the Spartan ID card.
Access the Spartan Hub then select Customize > Spartan ID > Service Tag. Change your tag other than the default.
What a Poser! (5 points):
Changed your Spartan’s pose in the Spartan ID card.
Access the Spartan Hub then select Customize > Spartan ID > Stance. Change your stance other than the default.
The Cartographer (5 points):
Created and saved a Custom Map in Forge.
Can be done offline, may need to install extra content from Disc 2. Select Infinity > Forge. Create a new map with the simplest settings then save it to unlock.
Game Changer (5 points):
Created and saved a Custom Game type in War Games.
Can be done offline, may need to install extra content from Disc 2. Select Infinity > War Games. Create a new map with the simplest settings then save it to unlock.
Snapshot! (5 points):
Saved a Screenshot from the Theater.
Select one of the custom maps you created then start the film. Take a screenshot and save to unlock.
The Director (5 points):
Saved a Film Clip from the Theater.
Select one of the custom maps you created then start the film. Record a clip and save to unlock.
Sharing is Caring (5 points):
Uploaded a File to your File Share.
Bromageddon (40 points):
Completed the Campaign cooperatively on Heroic or harder.