For what it's worth, you can look at the previous contest winners to get some idea of what they're looking for. I don't have a link, and am too lazy to google it, but you can probably find it if you try. In my dim recollection, however, I believe all three winning entries for serious not only voiced all the dialog, but had different people voicing each character. I can't remember if there was any foley (grunts and groans and whatnot).