The game is motion controlled, and gameplay is pretty simple -- tilt to go, and your little guy always just keeps swimming along. After he chows down for a bit (you can line up combos in succession for a slightly higher score), you can level up, and with each level comes a certain amount of customization. The first ding gives you the option to color your character as you'd like (one cool feature: you can choose to colorize your creature with a camera shot from the iPhone's camera), and others let you upgrade all kinds of biological additions: body shape, pincers, tails, eyes, antennae, and anything else you'd find on whatever was crawling around in the dirt way back when.
Some of the additions are cosmetic -- they don't do much for you in terms of gameplay. But some actually do help -- if you load up on antennae, you can up your perception, and see where food is when it's off the screen. Likewise, later in the game you'll encounter creatures that need a little more tact when trying to eat them -- they might have a hard shell you'll have to remove with pincers, or other protection that you'll need upgrades to get around.
There are about 35 levels (the EA rep said each takes around 3-5 minutes to "beat"), and every five levels, you're presented with a cavern to explore, like a maze to wander through. But we were fairly bored playing the game -- while the accelerometer is a good time, your character doesn't actually mean anything. There's zero connection between this game and the full version of Spore -- you can't bring your characters out into the Spore world, or see any other characters from other players wandering the iPhone game. It's completely standalone, and that makes it feel a little unconnected -- who cares about this little creature you control when all he'll ever be is a speck in a Petri dish?
Multiplayer was also rumored at one point, but it's not found here on the iPhone. The version of the game we played was actually an alpha, we were told, and the game is currently in beta at EA, so there's still a chance the WiFi multiplayer could be added (originally, players were supposed to be able to pit powered-up microbes against each other), but the PR person we spoke with seemed skeptical.
Spore Origins will come out in the iPhone's App Store on September 7th, the same day as the full game arrives for Mac and PC. As a replicate of the cellular stage in Spore, it's actually pretty good -- you can make some wacky wandering creatures, and the game looks good. But the actual gameplay leaves something to be desired, and considering the fact that EA has chosen not to give this one any hooks into any other parts of the Spore franchise, we sincerely doubt it will live up to expectations when released.