On each game page it says something like, "Submitted 22 hours before deadline." Is this because they worked on the games early, and decided not to work on the games later?
probably a lot of people throwing a few unity assets in a project and calling it day one ... or otherwise reusiing code to try to win a prize. I don't think i'll take all day (and i started late as it is) but anything submitted in less than 6 hours or so can't have been original, or tested at all.
I'd think twice before continuing project that looks like that it was clearly made before the jam... But usually need to give the benefit of doubt, and just have fun jamming :)