Unbreakable

Won 3 matches as Pavium (Multiplayer, Skirmish or Blitz)

Freeze!

Froze 50 squads with Cryo Abilities (Multiplayer, Skirmish or Blitz)

Marked for Death

Painted units using Pavium or Orbital Designator 30 times (Multiplayer, Skirmish, or Blitz)

Again with the Tentacles

Completed the 'Awakening the Nightmare' campaign on Heroic or higher

Clean up your Mess

Completed 'Manifestation' on any difficulty

The Ancient Enemy

Completed the 'Awakening the Nightmare' campaign on Legendary

Awake

Completed the 'Awakening the Nightmare' campaign on any difficulty

Before This Gets Out of Hand

Completed 'Manifestation' without the Proto-Gravemind exceeding 50% critical mass

Have You Tried Rebooting?

Completed 'The Archive' on any difficulty

Tapped

Completed 'Light the Fuse' on any difficulty

The Wave Breaks

Completed 'Fighting Retreat' on any difficulty

Serving a New Master

Completed 'What Could Go Wrong?' on any difficulty

Send in the experts

Completed Operation: Spearbreaker on Heroic difficulty

We go feet first!

Completed Operation: Spearbreaker on Legendary difficulty

Spear: Broken

Completed Operation: Spearbreaker on any difficulty

You've been busy

Won 3 matches as Commander Jerome (Multiplayer, Skirmish, or Blitz)

Trials of the Arbiter

Won 3 matches as The Arbiter (Multiplayer, Skirmish or Blitz)

And my shadow

Killed 25 units with Jerome's Command Mantis unit. (Multiplayer, Skirmish, or Blitz)

Time and place

Trapped 100 units with Stasis (Multiplayer, Skirmish, or Blitz)

Trash compactor

Destroyed 100 vehicles with anti-vehicle units (Multiplayer, Skirmish or Blitz)

Long-term commitment

Completed at least 1 Weekly Challenge each week for a month

The rank and file

Recruited or constructed 1 of each UNSC unit in Multiplayer or Skirmish (Launch units only)

Twisted Firestarter

Won 3 matches as Morgan Kinsano (Multiplayer, Skirmish or Blitz)

Meat grinder

Killed 100 infantry with anti-infantry units (Multiplayer, Skirmish or Blitz)

Man-to-freak communication

Killed 50 units with Forge's Warthog (Multiplayer, Skirmish or Blitz)

Space Healer

Casted 100 Healing Leader Powers (Multiplayer, Skirmish or Blitz)

Surviving the long war

Completed the Campaign on Legendary

Last stop, this town

Completed Last Stand

The hard fight

Completed the Campaign on Heroic

This war is over

Completed the Campaign

Sentinel size matters

Completed The Halo

Comrades in arms

Earned a gold medal on any mission (except Prologue) in Co-op on Legendary

Fifth floor: Tools, Guns, Super Weapons

Completed The Foundry

And the knockout punch

Completed Under the Dark

Natural intelligence

Played a Skirmish match alone against only AI opponents (1 or more)

Gold rush

Earned a gold medal on any mission (except Prologue) on any difficulty

Overkill

Destroyed 500 units with Leader Powers (Multiplayer, Skirmish or Blitz)

Flyswatter

Destroyed 100 air units with anti-air units (Multiplayer, Skirmish or Blitz)

Making the most of the day

Completed 3 Daily Challenges in one day

The tribe

Recruited or constructed 1 of each Banished unit in Multiplayer or Skirmish (Launch units only)

Heroes never die

Won 3 matches as Forge (Multiplayer, Skirmish or Blitz)

The setup …

Completed Hold the Line

Behind enemy lines

Completed From the Deep

The Scrappy Six

Completed a Multiplayer match as each of the 6 launch leaders (Matchmaking only)

Big Spender

Spent 100 Leader Points in Multiplayer or Skirmish

Just the facts

Collected half of the Campaign logs

Bear necessities

Built 10 Grizzlies (Multiplayer, Skirmish or Blitz)

Some light reading

Found a Campaign log

Duellist

Won your first Blitz match (Matchmaking only)

All travel is suspended

Completed Lights Out

Stirring the pot

Completed The Cartographer

The hand that feeds

Killed a unit owned by a developer or someone who has this achievement

Spare change

Spent 5 Leader Points in Multiplayer or Skirmish

First steps

Completed a Multiplayer match (Matchmaking only)

Guerilla tactics

Completed One Three Zero

Dominated

Completed Ascension

A history of decimation

Completed A New Enemy

Alas, poor Yorick!

Collected a Skull

Two heads are better than one

Completed a mission in co-op

Wake up

Completed The Signal