Cat game! Cat Game!! Wahoo!
I like the idea of blending the natural and unnatural (and I am curious if you'll talk about domestication and cats in urban spaces as well) and the focus on green transport is great. Paper prototypes and level layout looks great. I am having a bit of trouble understanding how the puzzles function, but there's a lot of promise in the concept.
+ I'm also excited to see how you'll develop the world!