Gmtk 2019 Update 1

The theme is `Only One`.

I brainstormed an idea last night and it turned out that it works best in 2D. So I'm not using Unity (too much bloat for 2D) and instead going for a "SFML/C++" thing. I should have a workable prototype by noon, if everything works out the way I want it to.

(Ron Howard voice, noon: It didn't.)