I have a question about the criteria, since trism came to me with concerns, and i've seem to come up with a bit of a hole in the criteria requirements which makes it VERY hard to pick a source.
Why aren't arcade games allowed? I've noticed that basically all the notable games released before the date in question were in fact released on arcades (donkey kong, ice climbers, mario bros etc) and they are very important parts of video game music history. As a result, if people who don't do chiptune style music, and don't have a vast in depth knowedge of games before this date, (which is most people) they've got to look into alot of obscure titles, from consoles they probably don't own (like C64 or famicom), only to find out that the games that are familiar to them were either released after the date you've picked or were in the arcades. Yes, you can still remix SMB, which is what I reckon all these people will end up doing, so you'll probably end up with at least 3 SMB overworld theme remixes, since its by far the most obvious choice and no one is going to be bothered enough to do the trivial research required to look into anything else
I understand the release date rule, but the arcade rule just seems to make things harder for everyone involved and rules out some important and historical games for no reason.
Sorry if i'm being awkward, but your criteria seems very hard to hit for some people depending on their skills and personal styles. I'd suggest criteria thats a little less "specialist" next time
EDIT: Bahamut actually beat me to the post, I was just asking some people to see if my concerns were valid.