Dude, I had the weirdest dream ever! I dreamed i was in this world, a video game, and it freaked me out a little.
The premise of the game is this: Think Pac-man, gobbling up all those dots, but works more like the game "The Wonderful End of The World", where I'm sucking up things smaller than me, but expands as I'm growing, allowing me to eat bigger and bigger objects. Unlike the game tho, it keeps going on and on and on into forever.
And not only that, but the world DO change as you're eating up, deciding which paths to take, what to eat, etc. Allowing for multiple replayability.
I'll give an example of how it works.
In the beginning, I'm a small bacteria, and I'm gobbling up smaller bacterias, while avoiding bigger ones. (If you ever played the game Spore, especially the cell phase, it works almost like that, but in a 3D format, not a side-scrolling version.)
There are many objects i can eat.... Do I decide to eat rocks? Do I drink water? Do I eat gases? Meat? Plants? Fire? Ice? Those decisions will determine how I evolve. Let's say I drink a lot of water.... I will grow to become a fish, and eventually into intelligent water-faring being. But what if I eat more rocks? I become not flesh, but a living rock being, growing crystals out of my body, and I eat rocks for nourishment.
What if I decide to suck in gases? Then I become one of the weird floating beings from a gas world, like Jupiter (with no lands to walk on).
What if I eat in a mix of elements? Like if I eat both meat and plants, and gases? Then most likely I will grow into a human, capable of eating both plants/meat and breathing air. Picture included for those that don't know what a human looks like.
What if I eat a mix of rocks and plants? Then I become like swamp thing.
Finally, once I'm past that phase, where it determines what form I take, I still gobble on and on.....
For simplicity's sake, let's say I'm a human boy. All around me, there are farmlands, there are villages, and there are castles. There are many things happening around me. (It is around dark ages, with lords battling over fiefdoms.) You can decide which paths to take- do you simply stay in the farmlands, eating crops, cows and the likes? In essence, it leads to the farming revolution.
Or do you go to the villages, eating up the people, scaring them away as you chase them down? Most likely you'll lead a crime spree, robbing people of their belongings.
Or do you go to the battlefields, where you pick a side, and devour the opposing side? The knights are quite big, so you need to eat up the smaller people, such as pages, squires, and other peons before you're able to take on the bigger bad guys. Depending on which sides you support, the world may adjust according to the winning side's ideals. Maybe one side support owning slaves? (Maybe lead to a world where you're able to lead a free-the-slave revolution, or eat up the slaves to keep the slaves in check.) One side supporting researching magic? (would lead to a world full of dragons, unicorns, and a dream-like world) Maybe one side support multiple nations, which would lead to a future world where the human race is split in warring nations? Or a world where there is only one nation, all the human race united in a common goal?
Or do you avoid the human race entirely? Maybe go up in the mountains, eating animals, trees, living out the rest of your existence in solitary, like a Bigfoot or a mountain hermit?
Depending on what you eat, the world would adjust according to the things you eat, what you spare.
It keeps on going like that, in different forms. Think of the same scenes playing out in a different setting, be it in a lava world, a gas giant world, an ice world, barren rock world, toxic world, aquatic world, and so on.... (As determined by the forms you take, what you breath and how you eat.)
Once you've grown beyond the human race (or whichever races you evolve into), you can then begin to eat the bigger objects, such as buildings, trees, even mountains and oceans. Do you act like the Godzilla, destroying the cities and having the armies attack you? Battleships, airplanes and tanks would all come out to fight you as you're invading. Hell, maybe you'll come across other big creatures to fight- so you need to eat more and more in order to combat those creatures?
Or do you avoid the people, eating other bigger objects? Maybe swim in the ocean, be like the kraken, growing bigger and bigger....
Or do you take to the skies, to control over all creation?
Even then, once you've grown too big for the world, you can start by eating the moons, and eventually the planets themselves, eating the occasional debris, asteroids, and so on. You would fly across the cosmos, combating other alien races, eventually come across HUGE objects you'll need to fight, like bigger spaceships, or death stars. You'll fight and eat TIE fighter versions at first, but then you'll upgrade to the star destroyers, ending in the stand-down with death star versions.
This goes on until you're able to consume entire suns, and eventually solar systems, and then galaxies. Once you've ate everything up, the end credits come up, and you can eat the letters as they come, but the end credit letters became bigger, so you need to eat the smaller letters quickly before the bigger letters overwhelms you. (Think Star War intro text, with the smaller texts on top, and the bigger texts on bottom.) Once you've ate the last of the letters, the entire screen goes black and the game's finished.
In short, a sandbox game of pac-man. That's the world I was stuck in! Weird!