The surface story is about aging metalheads who blame the influence of rap on the mainstream for them no longer being cool, but these characters would never have been considered anything but out of place, no matter which fad was/is in place.
Horror spoofs are rather tame, so Bill Zebub has created one that pushes the boundaries so far that you will wonder how the hell he got the cast to do those things on film. In these days, even offensiveness has become politically-correct. Watch The Worst Horror Move Ever Made and know what it's like to cringe. This movie is a re-make, with a new cast, plenty of gore and boobs, and superbly filmed.