Thanks for the comment. This is actually my fourth jam. I just couldn't think of a proper game idea until there are only 6 hours left for the jam lol, so not much has been done on the first two days.
i'd say next time just try doing something and the idea will come to you by itself, you don't need to think about it to get it, if you make something and play with it a bit the idea can popup to your mind!