A great demo, and creation game on its own.
In creature creator you do just what they name suggests, make amazing, funny, cute, killer, or what ever type of creature you want. You get all of the peices but only a 1/4 of them in the demo. You can stick them on as you please and then strech, squezz, fatten, or skinny up the part.
After combineding that the pieces you want together on your alien you can test him out. Make him, dance, punch, or do other actions with or without smaller (with eyes that are larger than they should be O_O) babies copying you.
It gets old very slowly but... it does after making lots but is a fun thing to do with a little time and for only 10$ it is highly worth it.
My Spore name is Closed btw.
(Just remembered... the creatures you make will be able to be used by you in the full game. People can see and battle or make piece with your creatures in the full game if you put them on the web.
http://www.spore.com/view/profile/Closed is my spore page.)