Think about the MVP. You need to separate an hour or two to makes notes. Create alot of questions about the idea you want to make. Then do as many answers as you can for each question and see what do you think might fit together and what you can make.
This should help you. I have a problem with overscoping too. Usually overthinking, but this was the first Jam that i managed to fit a project together and deliver it.
What engine did you use?