The patch allows you to play as one of your pre-made creatures by using a new cheat called 'evovantage'

There's the 'blocksmode' cheat (It's not really a cheat) that makes all of your creatures into blocks (You can go back to their normal appereance of course)

It fixes up some problems.

Better animations.

Hard difficulty is harder.

The creature phase is now better paced (meaning it doesn't drag on)

And it's free.

However, people HAVE reported taht their copy of Spore malfunctions a bit after donwloading the patch, but I have no problems with it.

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EA: Oh my you're out of ideas!

Will Wright: Yes, and you are ugly, however in the morning I shall have more ideas, and you shall still be ugly.