Well, I'm going to present my only good Super Mario Maker level. It's called Koopa Key Kastle.
Basically, the koopa's want to revolt against their king, because they've had enough of their tribe being eliminated. So they secretly help Mario destroy all of King Koopa's Kastle.
Though litle did the Koopa's know that they were giving Mario the key's too huge treasury, but they were making sure that Mario didn't know.
Now, fight Bowser and a hidden boss, explore under the castle, and steal all the coins!
Download: WiiU | 3DS