Here is the full list of all 11 They Always Run achievements.
Complete the Game
Find Out the Truth About Aiden
Carry All the Criminals in Your Arms
Defeat Mueller in the Second Fight
Find and Open 50 Chests in the Game
Get a Reward for 30 Wanted Bandits
Kill 100 Enemies with Pistols
Complete the Bounty Hunter Guild Test
Hand Over the Rat Alive
Kill Basim Salamander Instead of Stunning
Buy Ammo in the Store 25 Times