Sure, I'd be glad to!
Once the jam theme dropped we bounced some ideas around, primarily related to chaining explosions for the literal interpretation. We knew we wanted to go for some kind of setup/payoff gameplay, but we weren't sure how to thematically tie explosives to Doki as a character. Once the idea of having one bullet to set off the chain reaction was suggested, everything fell into place; we came up with the robots plotline shortly after that. We originally had the idea for there to be different helpers to set up the board for Doki to take the shot, but in the end settled on focusing on Mint due to her ghosty-ness being a perfect fit.
By the end of the first day we had the rough scope of the game planned out and had begun prototyping game mechanics and storywriting. We had most of the central game mechanics done by the end of the first week, with the remaining time spent on designing the robogoons, the boss, and the stages, as well as fleshing out the game as a whole.
We actually managed to get in almost all of the concepts we set out to do from day 1. I think the major thing we had to cut due to time was a Chonky robogoon variant. We also went back and forth a bit on how to handle the aiming laser precision; that's still not quite completely solved honestly, and we're hoping to improve on that experience after the jam ends.
Hope that gives some insight!