Trepang2
49 Achievements
GOG
That Was a Close One!
Kill an enemy with a headshot on final bullet in the mag
47.8%
How to unlock the That Was a Close One! achievement in Trepang2 - Definitive Guide
You're likely to get this at some point during the campaign by accident, but if you REALLY want it magdump the pistol the second you get it during Site 14, leaving only 1 bullet and shoot the next guy you'll find in the head.