Even the easy version ranks hard, but not quite Kaizo. The original version is definitely Kaizo though.
Some of the levels are weak edits of the original, such as the Yellow Switch Palace. The design is not very good: there are a lot of areas where you have to repeatedly jump between munchers set with one tile of space between them and through a bunch of generators (bullet, super koopa) and some damaging enemies or munchers are placed just above the line of sight, which isn't cool.
I found this to be a completely aggravating hack with a particular jump that seem luck-based even in the easy version since the only way to do it without hitting the muncher ceiling in that level is to run as fast as you can and hope you land on the cement blocks ahead. There's another jump like this in the hard version that I can't beat at all yet, and this is the premise of the entire hard version Yellow Switch Palace.
The start of the tide level will push you into a muncher immediately if you don't enter the level holding right AND a fish you couldn't see due to sprite tile memory problems will appear on top of your spawn point in under a second from entering the level. If you don't get the Yellow Switch before Yoshi's Island 3, you die instantly. The game likes cheap openings. Even a good Kaizo doesn't like to place this much necessary foresight on a player.
Some glitches exist: a sprite tile memory problem in the tide level is rather severe - I've had a Chargin' Chuck not only vanish but despawn when on top of a muncher after I hit him, causing an unfair hit. A lot of platform sprites in that level are either cut off or won't appear. One level has coins placed above music note blocks, which will cause an invisible solid block to appear. The layer 3 tide scrolls with the camera.
Graphically, this hack falls flat. There's a ton of cement block structures, some of which cut into dirt. There are no palette problems though since it uses default palettes.
You can access the original SMW from the castle onwards which I don't find very good for a demo - ideally it should shut off there. The overworld uses the original SMW's.