Not really a game, but...
Its a fun game and all the bizarre creatures that people make are fun to laugh at.
Its fun is a bit short lived if you have other stuff you can do as there really is no goal or anything you need to do. As a result of this I didn't play around with it too much, and just went on to play more Call of Duty 4 and Devil May Cry 4.
In the 15 hours I've played this I made about 10 creatures which ranged from slug monsters to the ever popular and laughed at penis monster. there are many possible parts and colors that you can use so that all your creatures can be unique and different from each other. my only real complaint is that there is really nothing to do once you finish your creature.