However, be aware that the game is not even close to a simulation of how evolution or, more specifically, natural selection actually works.
I saw an article where the creators of the game described the mechanics of Spore as a cross between evolution and intelligent design. That's approximately true, but only if you put the weight clearly on the intelligent design end of the scale.
The evolution (natural selection) part comes into play mainly with the struggle for your organism to survive. If you don't get enough food or if you don't defend yourself well enough against attacks, you die (go extinct). Manage to do the opposite and you have the chance to acquire additional physical characteristics. These improve your chances of surviving further challenges. That's it.
Unfortunately, this is a distorted view of the process of natural selection:
• First, there's no sex or reproduction of any kind (from what I have read online, mating and social behavior do play some role in later stages of the full Spore game; but not so in Spore Origins). In the real world, evolutionary success is virtually the same thing as differential reproductive success. Put another way, an organism that dies after producing a dozen offspring has a much greater effect on the species' evolution than a member that lives much longer but has no offspring. This alone pretty much eliminates Spore Origins from any serious consideration as an evolution simulation.
• Related to the first point, the competition that most contributes to evolutionary change is competition among members of the same species. Predator-prey interactions are secondary. They only matter to the extent that surviving such interactions provides an opportunity to leave more offspring than a competing member of the species. In Spore Origins, you are the only member of your species; there is no intra-species competition.
• In the real world, not all changes are positive. A change due to a mutation could leave an organism worse off than it was before. Other changes may prove beneficial at first but lose their value if and when the species' ecology shifts. Spore offers almost none of this. Although the features you can add may work better in some combinations than in others; all the features are designed to be "improvements."
• Evolutionary change via natural selection occurs within a population over generations -- as older animals die and are replaced by a younger generation. Over this time scale, the population characteristics of a species shift. Reproductively successful changes spread through the population; harmful ones do not. In contrast, change in Spore Origins occurs by a lone non-reproducing organism acquiring new physical characteristics over its potentially limitless lifetime.
This last point is critical to the evolution vs. intelligent design aspects of the game. An intelligent designer is someone that can arbitrarily select the characteristics of an organism, independent of any process of natural selection. That's primarily the way Spore Origins works. You are the "intelligent designer." You mete out changes as a reward for the creature surviving a game level.
While it is true that such changes can improve your creature's future survival probability, the process in Spore Origins is almost the opposite of how natural selection works. Natural selection does not "give" you an improved eye, for example, simply because you managed to survive with the "old" one. Rather, you get a modified eye first (typically via some random mutation) and, assuming the modification is beneficial, gain increased success as a result.
Bottom line: None of this detracts from the fun of playing Spore Origins -- as long as you realize that the game is not an evolution simulation. To the contrary, it is actually closer to an "intelligent design" simulation.
One more thing: EA should have provided more details as to the rules of the game. It was especially frustrating to find no explanation as to how evolution points are acquired (these are the points that unlock access to additional features for your creature). Apparently, you gain these points automatically when you complete certain levels; nothing else you do has any effect. I would have liked to have known this before I wasted time trying to uncover the "secret" of how to get these points. I still haven't found any official confirmation of this, not even on EA's Web site, so I may be wrong. However, a search the Web revealed many other users similarly unable to figure this out. So at least I am not alone here.