I tried out the X1 patch, and was a bit disappointed after looking up images of the X1 version. Lots of work clearly went into it, but the underground palette and castle palettes were unchanged from the NES palette, when the underground colors in the X1 version are supposed to be a more dark basic blue and the castles should be a dithered cyan color of sorts. Also, the Stars should have smiles, and the enemies' palettes should remain the same throughout every level type.
As for the game itself, I actually think SMB Special has pretty darned good level design. It seems more varied than the original so far from what I've played.