Cell Phase
Spore begins with a meteor crashing down onto a small, unknown planet. From within this meteor your cellular organism emerges.
This starts off the Cell Phase, the first of the game's five stages. The aim in this part of the game is to evolve and grow your creature so that it can move out of the tide pool and onto land. Depending on how you build your creature, there's numerous ways to accomplish this. Your creature's mouth determines what it can eat, and therefore dictates how you play this part of the game. Giving it a filter-feeder mouth means you'll have to swim around and find plant life to consume. If you equip your creature with a more carnivorous mouth you'll need to find smaller and weaker cells to prey on. Whilst you do all of this you'll also have to avoid larger predators who prey on you as well as fighting the continuous ocean current.
Eating other cells or plants will earn DNA points which can be spent in the cell editor. Here you can advance your cell by adding on or removing parts which will affect the abilities and behaviour of your cell. For example, adding more legs/tentacles will allow faster travel, allowing you to fight the current better and escape from larger predators. Adding on a second mouth would allow you to eat both plants and other cells (currently this is a theory and it is not confirmed as to whether or not adding two mouths is possible in the cell phase). Removing parts earns back DNA points. In addition, the cell editor allows you to modify your cell's appearance, making it more streamlined for speed, or larger to add extra strength. Dying in the cell phase resets the player back to an earlier evolution where DNA points must be earned back.
As you grow larger the blurry organisms in the background become more pronounced and eventually you'll rise to the surface enough to come up against them. Whilst the cell phase is often compared to flOw, this part is an exception in that rather than diving deeper you are attempting to reach the surface of the ocean. This is necessary to move on to land, however legs are not a requirment meaning when moving to the next phase your creature will be akin to a slug.
Spore's social simulation is evident from the first phase of the game. During the cell phase groups of similar cells will often be seen teaming up and working together to survive or take down a large opponent. This clear indication of social behaviours will continue to be evident throughout the game and play a much larger part in future phases.
To see this stage of the game in detail take a look at the Cell Phase preview. Now...onto the Creature Stage!
(Shamelessly stolen from: Planet Spore)