Iron Man
39 Achievements
1,000
12-15h
Xbox 360
Overkill
Defeat a soldier using the Unibeam
15
How to unlock the Overkill achievement in Iron Man - Definitive Guide
Target a soldier and hold RB for a second and release and you'll have unlocked the achievement.Easily done on First Flight mission.
This can be done on First Flight or any mission after. Kill all the enemies but one guy then land and charge an unibeam by holding down RB. Then unleash it on an enemy. Does not have to be full power just needs to be held down for at least a second. Make sure to aim straight at the enemy and be locked on before releasing. This has to be a foot-soldier, not a truck or helicopter.