I started working on my engine ~29 days before the jam started, which was a definite crunch time. There are so many things I’m changing as a result of this jam for sure!
Here is my engine if you’re curious: https://github.com/bluesillybeard/ZEngine. I highly recomend NOT using it unless you’re OK with using extremely early software.
And, I made a post with more details of my experience: https://itch.io/jam/acerola-jam-0/topic/3579185/my-experience-using-a-custom-game-engine