Not even sure if this is a bug or intended, and I couldn't find anything about it, but... The Sniper can headshot a Tank or Gunner from behind if you aim for where their is, even though you can't see it. Is this intended behavior or is their armor meant to protect them?
Second level passive sniper skill gives bullet penetration, so a head shot is possible from any angle. That's always one of my first upgrades, so I'm not really sure if it's possible without that.
I think the gunner's face-shield just eliminates his head as a hit box and makes it register as a body shot, so there's no worries about that.
