>>32989421I would create a game based on evolution; at the beginning of the game, you would receive a kind of amorph, slimy, colorless creature (let's call them EvoMon). Depending of the environment, it's activity and the way you treat it, it would evolve/grow/change differently. It would grow new organ, limb, horn, fur, change color, have body pattern, a certain diet, an unique personality and taste, ect... You would take care of it trough a kind PokeAmi interface, but more developed. There would be a shop who will sell product that would give unique change, such as rainbow coloration, plant organ (flower, leaf ect) and other cool stuff.
Battling would exist, but it wouldn't be the center of the game. There would be beauty or ability conquest, you could be a farmer/breeder and raise EvoMons that you will sell for money, be a caretaker who would take care of the EvoMons of other NPCs, be a kind scientist/professor who would work at a lab and make (more or less ethical) test on the EvoMons and trying to found/create unique evolution change, ect...
In short: a lot of stuff around the EvoMons.