I once thought of creating my own game, lol! What I came up with was a game called Survival. It is basically about you choosing, lets say, 1 of 5 environments (Sea, Mountainous, Desert, Grass lands/plains, and Rain Forest) to survive in using a certain animal in the category of that environment. So, you control the animal that you choose and you have to get through the levels, doing things like hunting, hiding and stuff like that. Also, for each environment, you could choose either the predator animals, or the prey animals.
I need to go, but im coming back to edit thisd later and add some more stuff...