liam - i've completed the game 100% and portland chainsaw massacre was one of the hardest mission!!! what you have to do is get an ak-47 and use the auto aim to start pumpping them full of bullets. when you can first see them on your screen sprint around then turn around and fire killing ONE each time. this might take longer than other ways but you do it first time.

i tried that and got murdered from those leonne bastards!!