great idea for a game, but I suggest you to come up with a reason to evolve and devolve,
like some place can only be past by using certain form, or each form has it's own unique advantage and weakness.
thanks. I had that idea that some parts could only be past by the small evophase and so on. But I am quite new on this and the time I got to level design and backstory I had only one hour left before submission. But I learned a lot