Mario Illusion World's a nice start, but I think it could use a little more polishing before it's feature worthy. There's actually a Star Road tile which doesn't connect properly and makes you get stuck off in the grass, but I haven't deleted it because the rest of the hack is well done.
I've always supported Mystery of the Seven Orbs for featured status. For some reason, I've never gotten around to playing Super Challenge World. (Really need to rectify that) If it's as well put together as Seven Orbs, it probably is feature worthy, too.
Although it is a very short demo of a one level hack that hasn't been moderated yet, ghost mansion has some pretty cool puzzles, although i don't think it should be featured until its a lot longer.
But i nominate it anyways.
And they were intentionaly glitched up, not just by accident, like some. A while back, I made one too, all I did was open every GFX file in the game in YY-CHR, and flipped them, it was glitchier that any game I have ever seen.