This version of "Killing Floor" requires that you play with commitment, attitude, aggression, and really smack those strings. As you watch along with the video, please note that I'm playing the riff by sounding the notes with all down strokes. This is a little unusual given the rhythm, but I think it sounds much better played this way. There's a noticeable difference in the sound of the downstroke and upstroke, down strokes just sound heavier. Fortunately, the riff is played the same exact way on the IV and V chords as it is on the I, so that makes our lives easier!
For the verse, we want to bring the dynamics down a little bit while keeping the intensity up. I do this by simplifying the riff and playing something similar to the intro. When I say simplify, I'm just implying that I subtracted some of the notes, unfortunately it's not all that simple to play. ;-) But once you get it, it sounds awesome and is a heck of a lot of fun to play!