This is an Example I made the other day, for Evil-Ville its shows how to make a platform AI, without using ANY detector objects and how to shange direction when it SEES the player in its line of site!.. all editable but minor documentation, I only documented where each component starts...
I've not tried it yet, but does it have any other features?
A nice one would be to have any enemies within a certain distance hear gunshots, or hear your footsteps if you run (so you gotta creep up on them).
Also maybe they can hide behind boxes for cover?