The Headshot skillshot is achieved by shooting an enemy in the head with certain weapons, like the Peace Maker Carbine, Screamer, Boneduster, or Head Hunter. It does not appear as though this skillshot is awarded when it conflicts with another skillshot that requires a headshot from a different weapon. For example, the Root Canal skillshot would not also award the Headshot skillshot, but a Headshot can be earned along with the Hotshot Skillshot.