So much potential in this - a few years ago myself and a bunch of friends were obsessed with ROM hacks for Super Mario World for the SNES; some of them were just really well-designed levels, and some of them were absolute hell, basically requiring the use of an emulator to save states and rewind. It created a completely different feel of game, and the simple and consistent physics of a Mario game was the perfect limitation for weird and strange things to happen.
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.
The recent Link Between Worlds for the 3DS is a direct sequel to the SNES Link to the Past, and in many ways, it's like a remix. I was skeptical, as I also adore LttP, but I really enjoyed the new one for the 3DS.
I figured this, and I'm less impressed with the particular run than I am with the design of the level. Everything fits together in just oh-so-perfect ways that make it deviously hard.
Here's a video of one of one of the difficult levels: https://www.youtube.com/watch?v=teAqRZX4hbY