I just bought Spore today and have been playing it for a couple hours now. The game sounded good and I had been thinking about buying it for a while now. The game is somewhat and I expected it to be, and totally different at the same time. It has a high customization potential, which I was expecting since it's from the creator of The Sims. There are all sorts of colors and patterns to choose from, and countless numbers of items and what not. Basically Spore is a game where you control the entire development of a species, starting with a single cell and growing into an interstellar society. The game is broken up into six different stages which are almost like different games. I have really like that feature so far. Just when the game play may start to get boring, you go to another stage and the game changes. The change from each stage is somewhat like going to a another level and things getting more complicated. However, the main goal of each stage is different so you don't feel like it just keeps getting harder and harder to do the same thing. I have made it to the fourth stage. I'll describe my experiences in each of the stages so far.

1. In this "stage" is mostly just a dramatic cinematic with a meteor falling to Earth. It breaks open and releases your first cell. Initially all you get to choose is whether your cell with be an herbivore or a carnivore.
2. This stage you swim around as a one-celled organism. The goal at this time to just to eat and grow. You can also collect medal things that unlock new traits. As you grow you can mate and create a new cell. When you do this you get to fully customize how the newly born cell will look. The food you eat gives you points that can be used towards buying body parts which you place on the cell. Once you have grown big enough you can sprout legs and move on to the next stage.
3. This stage you are a creature living on dry land. Now the goal is to gain DNA, which is done through either wiping out or becoming allies with other species. Like in the previous stage, you can mate when you have gain a considerable amount of DNA. Now the points come from doing the tasks to get DNA. The customization of the creature is basically the same as with the cell, but it is three dimensional and has far more options. As you gain more DNA your brain gets bigger and you can build a bigger pack of allied creatures. Once your brain is big enough your pack can become a tribe and move on to the next stage.
4. This stage you are no longer a particular organism but instead command the whole of the tribe. The creature the you were previously becomes the chieftain of the tribe. Now the goal is to conquer or team up with other tribes. At first your tribe is the only one and the other primitive creatures are still like animals. But soon some species start to form tribes as well. Now instead of customizing the physical traits of you species you choose the clothing of the tribe. You build up a town and make weapons and other things for the tribe to use. To feed your tribe and purchase thing you must acquire food by hunting the still primitive species. I have not gotten very far in this stage yet, and so this is all I know about it.

I have yet to play any of the other two stages yet, but Spore has been a very fun and different game so far. From my understanding the detailed level of customization gets applied to various other things in the later stages, like building vehicles and cities. The game was called "massively single player" on Wikipedia, but that aspect of the game does not really come in until the final stage. Basically your creatures and planet are automatically uploaded to the internet, and then all the other planets you encounter are all duplicates of those uploaded from other players games.If you are a fan or RTS titles or anything that is a new approach to video games you should certainly check this one out.