In the preview IGN tells how the looks of the creature editor have slightly changed, and how the editor itself works. Starting off with a vertebra, it's a matter of adding parts and stretching and morphing them to create the creature you like. The textures too are procedural, like the rest of the data. Giving your creature some colours can be done using several layers. While editing you can also preview the creature at any time, and see its animations. Creating a baby is possible too, which shows one or more little versions of your beast.
After the editor comes the game itself. During the demonstration Wright showed his creature in a world with a bunch of others, some of which are more social than others. Will also explained how there are editors for any element in the game, from flora to buildings and vehicles, and even planets. They're all customisable in one way or another. There's also a SporePedia bit in the game, a sort of card collection showing details of planets, creatures and more that you have discovered during the game.
Once you've taken the UFO to explore outer space, you get to explore other planets, possibly with life on them. During the demo he made contact to another herd of creatures, shooting off some fireworks to make them worship him. However, after picking up a creature and killing it, the city started defending itself by shooting the UFO. The UFO left and Will zoomed out some more, to show how the game can contain millions of planets and solar systems, ready to be explored. Check out the complete preview for more details, as well as the 18 minute video of the demonstration on the Media page. More from E3, from other sites, coming up later. We'll also have our own report up within the next couple of days.