This cheevo will be awarded for killing 30 human enemies with headshots.
The cheevo is as simple as it sounds, just aim for heads whenever you kill any human enemy.
It does not matter what weapon you use or if you shoot the body first as long as the final killing shot is to the head.
The game has many opportunities to work towards this cheevo but for me the mission "Frontline" has an abundance of "Reds" & "Reich" enemies for your headshot madness.
Keep in mind while working on this you can couple it with a few other cheevos at the same time.
If you have a scope, and keep further than 30m away and get headshots to work towards:
The Marksman achievement in Metro Redux worth 56 pointsKill 15 human enemies with Headshots from at least 30 meters' distance.
If you are using a pistol with a silencer you can also work towards the following 2 cheevos too:
The Cowboy achievement in Metro Redux worth 26 pointsKill 100 enemies using revolvers.
Happy headshots peeps