I find that when enemies are shot at and they run and try to regroup with more of their own. Also, when AI try to lead you into a trap. Can't remember the game, but there was this lone soilder/alien thing. I ran down the collidor after it in pursuit, and from each side of me i was ambushed :-O Cheeky buggers :o)
It's a hard one though... i suppose you could have different armies/squads, with their own tactics they like to use.
One thing that does annoy me, is when an enemy is hiding, and because the game "thinks" it can't be seen, doesn't seem to react to being shot. Like most humans, you'd be crappin yerself if someone was shoting at you. Especially if you got hit.
It's a hard one though... i suppose you could have different armies/squads, with their own tactics they like to use.
One thing that does annoy me, is when an enemy is hiding, and because the game "thinks" it can't be seen, doesn't seem to react to being shot. Like most humans, you'd be crappin yerself if someone was shoting at you. Especially if you got hit.