Coldglider is right : the overloading possibility during Halo 3 campaign is very restricted ... Actually, i've done it just once, with the "Unlimited Hornets + Unlimited Marines" during "Covenant Alliancy" mission (i did a funny advertisement video of it for my glitchers community forums : Halocalypse Now) , and the overload glitch in campaign only make just the map missed some textures, nothing else that could be helpful going into dark areas, i think.
But, in theory, if we find a glitch during New Mombasa Streets that allow us to have somme unlimited equipment, that could work ...
Tepec
you can overload on ODST with dead bodies you just need a turret and a friend then kill them X amount of times and the game will get laggy and deload a few objects
