Thanks so much for playing!!
Yes, can confirm the marble mechanics, tag barrel, most of the environment objects (battery and bulb terminals, campfires, lasers, freezing water...), were all done as part of the jam period. Aspects of the camera logic, some background logic for BGM, scene transitions, saving, some menus, started from Slime and were modified for this. In the end I ended up spending around 2/3 of the jam time on the new mechanics and getting all the systems up and running, which left a solid 10 days or so to build the entirety of the world haha.
Appreciate you taking the time to play the game and to leave a comment!