on the game page (which is not the jam page) it seems like you can send new files, try putting the updated version there
Viewing post in The hunt for the perfect recipe - UNFINISHED jam comments
I wanted to but uploads are disabled.
> Uploads are temporarily disabled because voting for GET LARGE Jam is in progress. You'll be able to make changes after the jam is over. If you delete a file it can not be recovered or re-uploaded until uploads are re-enabled.