Army of TWO The Devils Cartel
46 Achievements
1,000
Xbox 360
Headache
Perform 100 Headshots
30
How to unlock the Headache achievement in Army of TWO The Devils Cartel - Definitive Guide
I just took my time and aim you reticle at the head. Aim from behind cover if you keep getting shot at. I was able to get this during the 4th mission.