My guess is to differentiate 2 forms of music:
1. Music was made for games
2. Music was made just for fun
Criticals for 1:
Min 30 sec.
Criticals for 2:
Over 2 min.
Because how would you judge these songs one to another?:
It's to different.
And gamemusic is an another without the game!
And for jugement should work the hole AM Members!
I think about a poll.
Edit:I would say, 30 days the contest runs.Perhaps so long is the trial version of MM. So nobody could say: I don't have the programm, it's to expensive! (AND the download trial of MM2008 gives you everything you need to win the contest!):)