Though rated hard, it's very borderline between that and normal. What makes this hack "hard" are some of the puzzles, which often require thinking in terms of milking the enemies for all their use, whereabouts in the level look suspicious, and in one case in the Yellow Switch Palace, lightning-quick reflexes. One puzzle will require you to take a hit to get through, but it's completely avoidable, backtracking for the powerup is very easy, and the reward is worth it.
The platforming is intense. All the levels feel different and look great. There are areas where you'd think you were able to "break the level" but the way the author stuck coins in the hidden paths and other bonuses as well as a direct shortcut to a midway point while skipping one of the exits in another makes it evident it was all part of a plan to reward you for being sly. Even the more elaborate levels don't feel too cluttered, although there are occasional enemy clusters you will have to weave out of.
The only objective issue I can think of in this hack is how in the second level, there are areas where the powerups and enemies can go behind a background layer.
This is a very fun demo and I would play it again.