Yep, everything was built from scratch.
Unfortunately, developing the "Microbot engine" took so much time that I had to make the game itself a lot shorter than I originally intended.
Yea, creating your own engine is not an easy nor quick task, I also tried that one time, but it wasn't made for a jam, just for myself. It took me a few months to get everything in place (I used c++ and sdl for graphics).
Anyway, too bad jams doesn't let us vote for other criteria, but you have a big thumbs up for the effort c: