This may take a while to read. Why not make it a zombie survival adventure game? With customizable weaponary and custom characters? Something like cortex command? If you need a story, why not make scientists declare war for being underpayed and release a virus? And after hiking, your character (the one you created) is traveling back home. He finds his/hers family killed and tries to survive the zombie outbreak, and tries to find a cure? In the game, you could have choices, where to go, what action to do, what items to bring and what items to drop, so you don't exceed the weight. Bosses could be ones with massive sympto.... (fuck grammar, especially that word in paticular). You can meet survivors on the way, and recruit them, making them like npcs that follow you. Food and shelter n shit, think of a realistic zombie survival, only in 2d. I can delete this message if needed, but i would seriously play this game, even if it is a 2d game. Hope this helps