I'm also not sure if OOP is a religion to worship too long, it is also pretty old by now and the realization in C++ ... historically grown. But it is the heart and arteries of Godot.
I thought, from a maintainability pov, that putting the built-in hierarchy to use might be better than creating script hierarchies under a single node. But maybe I am wrong !
Edit: the cat game seems to be cute. Reminds me of Portal, is that similar ? Drone instead of tater, find way up, ... ? But I am more into simulation, also, since I had to give a small furry household-member because of a natural catastrophe I'll wait with putting small beings into danger until I have 1-3 new other ones to purr around the new house that's being built :-)