Complete the following achievements to unlock Xbox Live Gamerscore points.
Flooded (60 points): Complete all co-op missions.
Overachiever (100 points): Earn all co-op medals at least once.
Dynamic Duo (60 points): Earn all Gold stars in all co-op missions.
Extermination (60 points): Kill 10,000 enemies in co-op.
The Company of Strangers (20 points): Complete a co-op mission with at least 5 different players.
Overrun (20 points): Complete Operation A.
Switched On (20 points): Complete Operation B.
Switched Off (20 points): Complete Operation C.
Evacuated (20 points): Complete Operation D.
Terminated (20 points): Complete Operation E.
Escort Service (20 points): Keep all Wolverines intact in Operation A, Mission 3.
Nowhere to Hide (20 points): Prevent all Jackals from regenerating their shield in Operation B, Mission 3.
Never Knew What Hit Them (20 points): Kill a convoy target with every stationary gun in Operation C, Mission 3.
Brute Force (20 points): Finish the objectives using only the Brute Shot, melee and grenades in Operation D, Mission 1.
Foot Soldier (20 points): Finish the objective without using any vehicles/turrets in Operation E, Mission 4.
Recruit (20 points): Earn a star of any type in an operation mission.
Prodigy (20 points): Earn your first Gold star in an operation mission.
117 (40 points): Earn all Gold stars in all operation missions.
Distinguished Service (30 points): Earn all medals in the game at least once.
Weapon of Choice (10 points): Score a kill with every handheld weapon (excluding Rocket Launcher and Spartan Laser).
Powered by MJOLNIR (20 points): Use every ability at least once (excluding Overshield and Seeker Drone).
Skull Combo (20 points): Complete any mission with the maximum number of Skulls active.
Vidmaster Challenge (30 points): Complete Operation 5, Mission 1 with the Hollow and Black Eye Skulls active.
Extra Credit (20 points): Complete 75 challenges.
Pension Plan (20 points): Earn 25000 Spartan Points throughout your career.
Archeology (20 points): Complete Operation F.
Silvertip (20 points): Destroy all Mega Turrets with the Grizzly tank in Operation F, Mission 2.
Vidmaster Challenge 2.0 (30 points): Complete Operation F, Mission 4 with the Blind and Thunderstorm Skulls active.
The Enemy of my Friend (100 points): Get a higher individual score than your partner on all co-op missions.
Immune (100 points): Finish a co-op mission without becoming infected