I used to think that the origin of headshot, double kill, multi kill,... feature come from cross fire - an online game. Thanks to this answer, I re-think about the origin of this feature. I see that the mod called Quake sound is used to add this feature to Counter Strike. So I think that the origin maybe from the quake game. But after some research, I see that the headshot announcement may have come from Unreal Tournament instead.
What game first used announcements like headshot, double kill, and multi kill?