Playing the first level in Halo 3 trying to get the “Missing Link” & “Primate” achievements won’t unlock. Tried zooming in & out (with BR & visor zoom), shot them, threw grenades, melee them, started the level over several times, went forward into the level then backtracked. Can’t seem to get these to unlock at all.
I think you have to use a sniper to see them from a certain area. I remember glitching outside the map to see the missing link up close and the achievement wouldn’t unlock up close, only from inside the map.