Once you get the heavy beat down you can use the take down move to get the big guys. I always singled those guys out first. I like to try stealth as the first option by shooting or disabling alarms. If that isnt an option I open up from distance with sniper rifles and grenade launchers. The launcher takes care of the heavies and if not, I move in with the flamethrower as that burns em up good. My other weapon I carry is the desert eagle or the 44 for close in powerful quick shots.