Spore is so large it's hard to comprehend. You play as part god and part the creatures you create. Starting as a single cell organism you choose how you evolve, what you develop in the form of limbs, skills and attitudes all the way from cell to animal to tribesman all the way up to a member of your planets space program to go and discover other plants that are still at the cell stage. On top of this the whole game is online, so you will meet other players creations and societies during your travels.... you must try it!