i just hold it down and walk through the level and chop them up. fun fun fun. Its also fun against zombies, not Z secs or commandos tho. thats a bad idea.
I dare you to take that chainsaw through a Hellknight
I like the chainsaw myself... as for the hellknight thing. the most efficient weapon to use on a single hellknight is the chainsaw.. cause ou can take it out quickly and without taking damage. if there is more then one, then you need some fancy footwork to take them both out.