Full list of all 86 Halo 4 achievements worth 2,000 gamerscore. It takes around 25-30 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 49 achievements worth 1,000 Gamerscore, and there are 5 DLC packs containing 37 achievements worth 1,000 Gamerscore.
Complete mission 1 on any difficulty.
Complete mission 2 on any difficulty.
Complete mission 3 on any difficulty.
Complete mission 4 on any difficulty.
Complete mission 5 on any difficulty.
Complete mission 6 on any difficulty.
Complete mission 7 on any difficulty.
Complete mission 8 on any difficulty.
Complete the Campaign on Normal or harder.
Complete the Campaign on Heroic or harder.
Complete the Campaign on Legendary difficulty.
Complete the Campaign solo on Legendary difficulty.
Complete any Campaign mission with 3 or more Skulls on Heroic or harder.
Complete any Campaign mission cooperatively on Heroic or harder.
Find a Terminal in the Campaign.
Find all of the Terminals in the Campaign.
In mission 1, find and access Chief's record.
In mission 2, get significant air in the Warthog at midnight.
In mission 3, carry a UNSC weapon all the way through on Heroic or harder.
Complete mission 4 without one preventable Marine death on Heroic or harder.
In mission 5, steal a Wraith and use it to kill at least four enemy Wraiths on Heroic or harder.
In mission 6, trick or force a Hunter to fall to his demise.
In Mission 7, in solo Campaign, take out both Hunters using only the Sticky Detonator.
In mission 8, kill 3 Crawlers in one hit with the Gravity Hammer.
Rank up your Spartan-IV to SR-5.
Rank up your Spartan-IV to SR-20.
Win 5 War Games matchmaking matches.
Win 20 War Games matchmaking matches.
Complete a Spartan Ops Mission on any difficulty.
Complete all chapters in Spartan Ops Episode 1 on Legendary difficulty.
Complete all chapters in any 5 episodes of Spartan Ops on any difficulty.
Complete a Spartan Ops chapter solo on Legendary.
Find one of the RvB Easter Eggs in Episodes 1 to 5 of Spartan Ops.
Save at least one Marine in Chapter 3 of Episode 2 of Spartan Ops on Heroic or harder.
Assassinate a Knight in any Spartan Ops mission.
Complete Chapter 4, Episode 5 of Spartan Ops without losing a generator on Heroic or harder.
In Ch 1, Ep 5 of Spartan Ops survive the enemy assault during the defense on Normal or harder.
Complete a Challenge.
Complete 25 Challenges.
Change your Spartan's armor in the Spartan Armor card.
Change your Emblem in the Spartan ID card.
Change your Service Tag in the Spartan ID card.
Change your Spartan's pose in the Spartan ID card.
Create and save a Custom Map in Forge.
Create and save a Custom Game type in War Games.
Save a Screenshot from the Theater.
Save a Film Clip from the Theater.
Upload a File to your File Share.
Complete the Campaign cooperatively on Heroic or harder.
In Crimson DLC matchmaking, get a kill while airborne in a Warthog.
In Crimson DLC matchmaking, kill 20 enemies with a detached Machine Gun Turret.
In Crimson DLC matchmaking, kill a player while airborne from a Man Cannon.
In Crimson DLC matchmaking, kill 20 enemies using the Mantis' stomp attack.
In Crimson DLC matchmaking, board an enemy Mantis.
In Crimson DLC matchmaking, score the killing blow on a Mantis.
In Crimson DLC matchmaking, shoot an enemy who’s airborne from a Man Cannon.
In Crimson DLC matchmaking, kill an enemy with melee when landing from a Man Cannon.
In Majestic DLC matchmaking, assassinate an enemy who's in zoom mode.
In Majestic DLC matchmaking, perform 5 'airsassinations.'
In Majestic DLC matchmaking, get the 'Close Call' medal twice during one match.
In Majestic DLC matchmaking, kill 5 enemies while Promethean Vision is active.
In Majestic DLC matchmaking, kill 5 enemies while Active Camo is active.
In Majestic DLC matchmaking, get a Double Kill or higher with one Pulse Grenade.
In Majestic DLC matchmaking, get 4 kills using the SAW without dying.
In Majestic DLC matchmaking, kill 3 enemies while they are using Jet Packs.
In Majestic DLC matchmaking, call in 3 ordnance drops during the same game.
In Majestic DLC matchmaking, perform a melee kill right after using Thrust Pack.
In Castle DLC matchmaking, disable a vehicle and then hijack it.
In Castle DLC matchmaking, get two direct Spartan Laser kills in one match.
In Castle DLC matchmaking, heal a near-death teammate with Regen Field 5 times.
In Castle DLC matchmaking, assassinate an enemy who is using a Hardlight Shield.
In Castle DLC matchmaking, disintegrate 6 enemies using Forerunner weapons.
In Castle DLC matchmaking, perform 5 melee kills in a single match.
In Castle DLC matchmaking, complete a match in any mode for each Castle map.
In Castle DLC matchmaking, destroy 2 vehicles during a single game.
In Castle DLC matchmaking, kill 5 enemies during a match by running them over.
In matchmaking, assassinate the ball carrier within five meters of your own goal in Ricochet.
In matchmaking, score three times in one round of Ricochet.
In matchmaking, score by throwing the ball from 30 meters in Ricochet.
In matchmaking, survive three vehicle explosions in a row with the Survivor package.
In matchmaking, score a goal in Ricochet while taking damage with the Resistor active.
In matchmaking, recover full shields from low health with both Resistor and Recharge active.
In matchmaking, effectively camp one location without dying for a full 60 seconds.
In matchmaking, get four consecutive kills with the Rocket Launcher without dying.
In Bullseye DLC matchmaking, activate both electrical surge systems during a match on Vertigo.
In Bullseye DLC matchmaking, acquire the Rocket Launcher at the start of a match on Pitfall.