Thank you. It is true, the game is not well balanced yet.
I started developing this morning so I didn't have much time to playtest it XD
Notably, the bunnies don't have AI, so the foxes eat them too quickly.
It was indeed the goal to allow the player to create an indefinite balance.
It should be pretty simple to add it*, I just ran out of time.
Thanks for the feedback.
(*Perhaps the simplest solution would be to write a genetic algorithm to mutate my game, optimizing for Score. Hahah.
By "simple" I mean "just adjust some parameters". However the parameters are exponential and there is a multi-dimensional search space!)