Army of Two Unlockables
It is my knowledge that Army of Two does contain a few unlockable weapons that can be unlocked via special pre-order codes, however, I believe the codes are specific to your pre-order, and cannot be used repeatedly. If you have knowledge of codes that can be used by more than one person please let me know and I will add that information here.
Army of Two Achievements
The following achievements are available for Army of Two on the Xbox 360 video game console. To unlock an achievement, simply perform the indicated task. Doing so will unlock the achievement and the associated gamerscore points. It also appears I may be missing one achievement, if you happen to see it (its more than likely a secret achievement), please let me know.
Alright, Who Wants Some? - 20 points.
Kill 250 enemies total using SMGs.
Beast with Two Fronts - 20 points.
Kill 50 enemies total in Back-to-Back.
Big Boom! Big Bada Boom! - 20 points.
Kill 25 enemies total using RPGs.
Boots on the Ground - 10 points.
Finish playing a versus ranked match.
Dead Man's Hand - 20 points.
Kill 150 enemies total using Handguns.
Elite PMC - 50 points.
Complete all missions as a Professional.
Fear is The Mind Killer - 45 points.
Spend 1 minute straight at full Aggro.
Field Medic - 30 points.
Drag and heal your partner 25 times.
Fission Mailed - 20 points.
Kill 25 Martyrs by shooting the Bomb Packs on their chests.
Flip You. Flip You For Real - 20 points.
Kill 50 enemies total using the Melee Attack.
If I Were a Rich Man - 40 points.
Earn one million dollars in total over the course of campaign mode.
If It Bleeds, We Can Kill It - 30 points.
Kill 25 Heavy Armor enemies.
L'Abattoir - 30 points.
Kill 100 enemies while in the power mode of Overkill.
Man of Many Masks - 50 points.
Purchase every mask variant.
My Kind of Case! - 40 points.
Collect all of the information cases in the entire game.
My Virtual Friend - 35 points.
Complete all missions with the Partner AI.
One Gun is Enough - 35 points.
Win a ranked match without purchasing any additional weapons.
One Shot. One Kill. - 20 points.
Kill 100 enemies total using Sniper Rifles.
Out of Debt - 15 points.
Heal your partner for the first time. Training does not count.
Retirement Savings Plan - 40 points.
Earn one billion dollars in total in ranked matches.
Running Man - 30 points.
Kill 75 enemies while in the stealth mode of Overkill.
Say Hello to my Little Friends - 45 points.
Purchase the MP7, M134, DAO-X Protecta, MGL MK-X, and the M107 Light Fifty.
Seven-six-two Millimeter - 20 points.
Kill 250 enemies total using Assault Rifles.
Spray and Pray - 20 points.
Kill 250 enemies total using Machine Guns.
Starting a Riot - 30 points.
Kill 50 enemies total in Co-op Riot Shield.
Stonewall - 30 points.
Kill 30 enemies using the Riot Shield melee attack
Surviving The Game - 25 points.
Complete a ranked match without ever needing to be revived.
The Devil's in the Details - 20 points.
Complete 20 minor objectives in a ranked match.
This is my Boom Stick! - 20 points.
Kill 250 enemies total using Shotguns.
Two Eyes are Better Than One - 35 points.
Kill 5 enemies total using Co-op Snipe.
Weapon Specialist - 15 points.
Purchase 3 weapons.