I've never see Kaizo Mario World before. That's amazingly clever. It's easy to just, say, spam a screenful of koopas at you to make something hard. These levels, though are hard because they involve a complex interaction of Mario skills, with zero tolerance for getting it wrong. If you've played enough Mario, some of the sections are actually funny in the same way that comics are: I immediately see how difficult the task is, why, and the combination of both almost makes me laugh.

I actually threw up my hands when I saw not only that the player had to throw a baby Yoshi up in the air to eat an enemy, but that the designer of the level expected this! Same when I realized that the the length of an area was tuned so that it was juuuuuust smaller than the amount of time Yoshi held a shell in his mouth before swallowing.