The design is okay-ish. I don't complain about it; even if there's not much variety, it still is fun enough to get trough. Of the 4 levels, I disliked the last two (the level with the boos and the castle), the former, being an huge difficulty spike compared to the global difficulty of the hack, and the latter, being too easy for a castle level, mostly because there are not many enemies, and also because most of the level is empty. On the brighter side, the first two levels are good. Making an overall, I'd say that the design is 50% good and 50% bad.
Can't be said much about aesthetics, where the author only used SMW elements (including palettes). The assembling is nice, although there is some silly cutoff in the boos level.
As only issue, music breaks on accurate emulators.
Overall, a very small, standard-ish demo. Not sure if I'd recommend it.