For me personally, it was finding an idea that could fit the theme of the jam. I spent most of the first day developing base shooter mechanics and seeing what could make for an interesting idea.
Give and You Shall Receive is a wave-based survival game where the player must survive hordes of enemies by gunning them down. The catch is that after every wave, the player must choose to give up something in order to receive something in return, changing up how they play the game.
https://mark-auman.itch.io/give-and-you-shall-receive
What about for you?