Like Spore on the DS, the mobile version of the game doesn't even try include everything from the PC version. Spore for phones centers on the Cell Phase of the game. You use the phone's joystick to steer the creature through a slurry of suspended protein and other early life forms, eating objects and avoiding enemies.
But like the other versions of Spore, you'll regularly use a creature editor to upgrade the character. While the body part choices are also scaled down, there's enough variety to make the creature your own. Certain parts, like a dangling lure, affect how other organisms behave. That lure attracts food to you, for example. Or you could add a shell for personal defense; hit a button, and hide inside for temporary invulnerability.