Here is the full list of all 46 Army of TWO: The Devil's Cartel achievements worth 1,000 gamerscore.
Perform 10 melee kills on wounded targets
Kill 10 Brutes in Physical Confrontation
Buy All Outfits
Buy all Weapons, Tattoos, Masks and Outfits
Complete the game on Insane
Perform 50 Backstabs
100 targets killed using either an MMG or an MGL
200 targets killed in double Overkill
Level up to Rank 25
500 targets killed while in cover
Buy All Guns
Kill 3 targets or more using an explosive object in any level
200 targets killed in single Overkill (Triggered by your partner)
200 targets killed in single Overkill (Triggered by you)
Perform a x10 Co-op Combo
Destroy 50 cars
Complete Confrontation
Complete the Campaign
Complete Assault
Headshot a target while blind firing
Complete Narco Hell
Destroyed 500 objects
Level up to Rank 15
You took the Aggro for 100 Flank kills
Create your own Custom Mask
Apply the maximum number of layers on a customized mask
Complete Enemy Territory
Perform 250 Flank, Surprise and/or Tag Team kills
Fully customize a weapon with 6 customizable parts or more
Complete Salvation
Perform 100 Headshots
Complete Last Resort
You didn’t go wounded once in a mission (medium, hard or insane)
Perform 10 cover to cover transition in a row
Complete Outside Contact
Perform 100 melee kills
Players simultaneously killed 2 unaware targets
Kill 3 targets with 1 grenade
Complete Rally Point
Complete a mission (excluding New Blood) with a human partner
Level up to Rank 5
Complete Cause and Effect
Perform 50 Hat Shots
Perform a melee kill while you're in Overkill
Make your first kill as a rookie (in Cause and Effect mission)
Complete New Blood