Complete the following achievements to unlock Xbox Live Gamerscore points.

Elite PMC (50 points): Complete all missions as a Professional. 
My Virtual Friend (35 points): Complete all missions with the Partner AI. 
Say Hello to my Little Friends (45 points): Purchase the MP7, M134, DAO-X Protecta, 
MGL MK-X, and the M107 Light Fifty. 
Man of Many Masks (50 points): Purchase every mask variant. 
If I Were a Rich Man (40 points): Earn one million dollars in total over the course 
of campaign mode. 
Fear is The Mind Killer (45 points): Spend 1 minute straight at full Aggro. 
Starting a Riot (30 points): Kill 50 enemies total in Co-op Riot Shield. 
Two Eyes are Better Than One (35 points): Kill 5 enemies total using Co-op Snipe. 
Seven-six-two Millimeter (20 points): Kill 250 enemies total using Assault Rifles. 
This is my Boom Stick! (20 points): Kill 250 enemies total using Shotguns. 
Spray and Pray (20 points): Kill 250 enemies total using Machine Guns. 
Dead Man's Hand (20 points): Kill 150 enemies total using Handguns. 
Alright, Who Wants Some? (20 points): Kill 250 enemies total using SMGs. 
One Shot. One Kill. (20 points): Kill 100 enemies total using Sniper Rifles. 
Big Boom! Big Bada Boom! (20 points): Kill 25 enemies total using RPGs. 
Flip You. Flip You For Real (20 points): Kill 50 enemies total using the Melee Attack. 
Fission Mailed (20 points): Kill 25 Martyrs by shooting the Bomb Packs on their chests. 
If It Bleeds, We Can Kill It (30 points): Kill 25 Heavy Armor enemies. 
Field Medic (30 points): Drag and heal your partner 25 times. 
Boots on the Ground (10 points): Finish playing a versus ranked match. 
The Devil's in the Details (20 points): Complete 20 minor objectives in a ranked match. 
Surviving The Game (25 points): Complete a ranked match without ever needing to be revived. 
Retirement Savings Plan (40 points): Earn one billion dollars in total in ranked matches. 
Out of Debt (15 points): Heal your partner for the first time. Training does not count. 
One Gun is Enough (35 points): Win a ranked match without purchasing any additional weapons. 
Beast with Two Fronts (20 points): Kill 50 enemies total in Back-to-Back. 
Running Man (30 points): Kill 75 enemies while in the stealth mode of Overkill. 
L'Abattoir (30 points): Kill 100 enemies while in the power mode of Overkill. 
Weapon Specialist (15 points): Purchase 3 weapons. 
Stonewall (30 points): Kill 30 enemies using the Riot Shield melee attack 
My Kind of Case! (40 points): Collect all of the information cases in the entire game.