Kaizo Mario is a homebrew level for Super Mario World that’s equal parts evil and genius. My tolerance for frustration isn’t nearly high enough to be able to handle this, but for those of you looking for a gaming challenge, there’s a link to the ROM below.
You can make your own custom levels for Super Mario World with a graphical level editor called Lunar Magic. You’ll need a Windows PC and the original SNES Super Mario World ROM to use it. If you come up with anything you’d like to share, please add it to the comments.