Spore starts small. A simple life form--you, specifically--merrily swims around in primordial goo, absorbing nutrients. Nothing matters outside of this pool, not the rock basin that holds it, the continent that cradles the rock basin, the planet that holds the continent, the solar system that contains the planet, or the galaxy that surrounds the solar system.

None of that matters--yet. Spore keeps its focus on the immediate goal, a race to survive and grow. Just like those scaling worlds, there’s always a hungry creature bigger than you.

Spore ends big. Your fully developed species extends its reach beyond its home planet, exploring and colonizing worlds across the galaxy. Literally, a million stars with about four planets each hold other creatures and civilizations, or may be barren and ready for development. All of them are unique, and all can be explored.

Spore is about the evolution of your organism: the transition to land, the development of appendages and teeth, the invention of tools and tribes, and the creation of global societies. The game simulates life evolving over billions of years while drunkenly zooming back like the Eames short “Powers of Ten.” And the result is playful, experimental, and explorative, as we found in our recent demo.

Seeds of Spore. EA says it will release Spore for Macs on the same day as the PC version, September 7. Spore will use TransGaming’s Cider technology, meaning it’ll require an Intel Mac.

Spore’s chief designer, Will Wright, defined the sim genre with SimCity, emphasizing creativity and play versus strict objectives. His later follow-up, The Sims, took simulation to the interpersonal level, experimenting with relationships in a dollhouse-like family. With the help of a massive team of developers, Spore builds on these themes, letting players interact with the game any way they want.

Players can start at any of its five evolutionary phases—cell, creature, tribal, civilization, and space—or progress through each in a linear pattern. Or gamers could just get sucked into the many building tools, endlessly creating whimsical life forms, buildings, and vehicles. There’s no right way to play Spore, although it has enough objectives to steer those of us who want more guidance.

About the space exploration phase, Wright said, “Different players will come at this with totally different styles. You might just play this totally aggressively and conquer all these neighbors. You might want to make allies with all of them.... We want the game to basically accommodate all of these different play styles. And I just want to be creative and [go around] looking for cool planets. But for the players who want a hardcore challenge, that’s what it’s going to be.”

Spore evolution, a series of funny hats.

Creature comforts. Creature editors are the root of Spore’s creativity, a cross between Mr. Potato Head and Maya. After earning enough points and upgrade options--typically through eating enemies--you’ll be able to swap in an assortment of dozens of parts. Each trait directly impacts the creature’s performance in the world. Bigger arms pump up strength, extra legs boost movement, and a spiked tail adds an always-ready weapon. But the part roster includes horns, antlers, noses, mouths, and practically any other body part.

Those parts can go nearly anywhere. Instead of pre-planned animation, a procedural graphics engine figures out how your choice and position of parts affect the creature. Stick stocky legs at the back of a body, and the game makes the creature wobble. Add a third leg for awkward ambling. You control neck length, body shape, and nearly everything else, and the game automatically brings your creature to life.

EA expects that some gamers will play with the creature editor almost exclusively. Sometime before the Spore launch--the company wouldn’t specify when--EA plans to release a creature-only version of the title, letting gamers model and play with new species.