Kaizo Mario World

Akihabara: Back in the day this level looked brutal, but now it seems much tamer lol. Most setups are simple in terms of kaizo, and with some skill, they're easy to execute consistently. Between bouncing on Bullet Bills, riding a Spiny, Chuck gate and of course, kaizo blocks, this level brought to light many staples of kaizo design. The hardest setups in this for me were the spin-jump on a Bob-Omb right before the midway gate, and the second Piranha riding setup that goes into a Turn Block Bridge. For the latter, i found a way to consistently drop without even jumping on the Piranha, so that was neat! haha

Death Palace: Possibly the easiest level in the hack. I like the way we can take our own time on the way to the P-Switch, and then have to rush back after activating it. The use of Thwomps and Ball n Chain really kicked off most of kaizo's enemy bouncing design. This has no real difficulty spike, but i used to struggle with the kaizo block in the Paragoomba setup lol. This is a short and fun level!

River Dyx: The (in)famous Dolphin level. I have to say, i actually find this level super fun for the most part. The dolphin setups are very creative. Some of my favorites being the 1-tile corridor walks while avoiding the dolphins, and also some of the Sawblade jumps. The only dreadful setups being the jump on dolphins right after the midway gate, due to RNG, and then the ending setup with the Fishing Boo... because it's a Fishing Boo.

Cerulean Cave: This level... I'd easily rate this as the worst level in Kaizo Mario World, and all because of two jumps. Not gonna lie, most of the level itself is actually fun! The Yoshi feeding part is really neat, one of my favorite segments in the hack! i like the way the section mixes low jumps and high jumps, and with the autoscroller, there are nice ways to time your jumps properly. And then comes the second half, which gave birth to a very common kaizo mechanic: The fast autoscroller. Too bad it had to come in the worst way possible, where the section ends with two (or three even) absurdly precise jumps that make the entire level a chore to beat, between the jump on the falling platform, the kaizo block right before that, and the frame perfect pipe entry at the end, this whole ending section is downright stupid. After needing to try these last jumps for 2 hours (while the rest of the level took merely 10 minutes), all the enjoyment i had in the first half was long gone. I talked about how i could find a consistent way to time most hard setups in the hack, but no matter how much i tried, the two last jumps just never worked. It was just a matter of exhaustively trying until i got lucky with them.
In the past i would say Ultra Star was the hardest level in this hack (excluding the Special World), but now i definitely consider this harder than Ultra Star.

Aneha's House: A puzzle in a kaizo hack, not something you see often. This level is overall pretty easy, and even figuring out the puzzle isn't hard. There's also a well known skip with a spring jump in the sublevel. I think in general, this level has an interesting structure to it, with the progress coming in layers as we get access to new items in the main area, although none of the sections really stand out on their own. The best and hardest part of it is the Big Boo bossfight, i find it really cool how many layers the fight has, with the Fishing Boo, the Eeries and the jump-grabs. Despite how many things are happening, i found this fight to be pretty fun!

Dead Sea: A water level. I know some people will disagree with me, but i really like this level! This is the level that showed me how much potential SMW water mechanics have, between holding down to swim low and holding up to swim high, there's a lot of variety to control water movement, and this level really puts it all to good use! I like the way the level is structured, usually requiring control of Mario's water movement to avoid enemies or navigate tight spaces. The only thing i'm not a fan of is the Bullet Bill generators, since they can be unfair at times.
Overall, i think this is a great level! And it also allows farming 99 lives with the Koopa Shells hehe, so it really contributed with making "savestateless" actually possible in this hack.

Hell or Heaven: This might actually be easier than Death Palace, depending on the player's experience with Cloud controls. I'm used to controlling a Cloud, so i didn't have trouble with this. It is a slow level with some careful movement required, but overall it is pretty short, and there isn't really any setup that stands out as being hard. I'd say the only thing that can be dangerous is the Magikoopa, since it can appear anywhere.

Ultra Star: Ultra Star is a level that needs no introduction, it basically shaped kaizo to be what it is today, and it's so iconic that every kaizo made back in the day had an Ultra Star level. It is also one of my favorite levels from this hack! I think it is very well designed and has a great movement flow, it's really satisfying to play! It is also one of the hardest levels in the hack, for sure, requiring a lot of precision and quick movements, especially in the second half with the Timed Lifts. It is also known for having some brutal kaizo blocks, the one before the first Scale Platforms and the one below an On/Off block come to mind lol. Yet, despite all of this, i've found it to be much easier now with my current kaizo skills, and even on some of the hardest jumps, i've found a way to consistently get them, mostly by using visual cues or careful positioning. I consider the hardest jumps to be: The jump leading to the first Scale Platforms, the first Timed Lift after the checkpoint, and the jump on the 4-1-4 Timed Lifts right after that.
I remember the first time i beat this level in 2019, it took me over 800 deaths (by the fact i got 8 Game Overs after starting at 99 lives), yet this time it took me about 130 deaths. I used to consider this level the hardest in the hack, but now i think i'll rate it as third hardest (behind Cerulean Cave and Special Stage 3), because while it is difficult, at least it's consistent.

Cultural Importance: Another kaizo staple, the 5 room final castle with no checkpoint. A very interesting format, i have to say. Each room offers a nice bite-size sample of kaizo design that is overall very fun to play! It can be dreadful to play the first few over and over again everytime you die on a later room, yet i think having the opportunity to get consistent in a small room, to the point you can oneshot it almost everytime, makes them less of an issue than having to replay a full length level.
I've always considered rooms 2 and 3 to be the hardest in this level: Room 2 because of the first Thwomp bounce, which i still find a little hard to get consistently, and room 3 because of the third Dolphin jump, which i think is a 2 or 3 frame window to get past. I used to think this Dolphin jump was the hardest jump in the entire hack, even harder than the pipe entry in Cerulean Cave, but now i've changed my opinion, as i was surprised to find a visual cue to do it with some decent consistency!
After we're through the 5 main rooms, the Bowser fight is more a novelty than actually a challenge.

Special Stage 1: Oh boy, this level. I have a lot to say on this one. I've known of this level for as long as i've played this hack, and it always seemed to be the most dreadful and miserable experience a kaizo player could have. The infamous "RNG jump" at the start of this level is probably the most intimidating setup of this hack, simply because of how unrealistic it seems to be when you're just looking at it. And i have to say, this jump alone was the reason i didn't even attempt the Special World back in 2019 when i beat the main route.
But today, things have changed. I've decided to not shy away from challenges, and i was set on beating this hack 100%, which means i had to complete this level. Throughout the entire playthrough i was dreading the point i'd get here. And then when i finally did... i was surprised. This level ended up being more enjoyable than i imagined!
At first it was really difficult. In fact, the first thing i did was savestate practice the rest of the level, before i even decided to attempt the first jump. And i found out it seemed to be pretty manageable. While the Cheep Cheep Generator is annoying, it wasn't as intrusive in the rest of the level, and thankfully there are ways to make it much easier on us. There's always a safe spot to stay and wait for the right moment to progress, and on the second shell escort, i found it easier to actually go to the end without the shell, stop the Cheep Cheep Generator, and then come back for the shell.
So after some practicing and figuring out the level was doable, it was time to tackle the beginning jump. Trying it blindly wasn't gonna cut it, i needed something consistent, so i focused on trying to find a consistent timing, or some sort of cue for it. And after a while, i actually did! While the RNG seems to be impossible to master, the start of it is somewhat consistent, the order of the first 5 Cheep Cheeps is always the same, with only their timing and positioning changing. So with a certain order of inputs i was able to find a timing that adapted to a few of the RNG patterns. This means that i would do the same movements at every attempt and, if the RNG was favorable, the Cheep Cheep would spawn on the right place for me to jump. This improved my success rate by a lot! When i started attempting it, in the first set of 99 lives i used, i got the jump correctly 3 or 4 times. By the time i beat it, i was getting the first jump about 70% of the time.
Aside from the first jump, the last one was also really difficult. I didn't find a way to properly time it, it was all about momentum and midair movement. And on top of that there's a Chuck guarding the pipe (and even though i was able to keep the shell, for some reason half the time i would die to the Chuck even when i was holding the shell while colliding with him...). Thankfully, i only had to get this jump once. This level was the one that took me the longest to beat, but i don't consider it the hardest, a lot of that time was figuring things out.

Special Stage 2: The easiest Special Stage. I like the idea of a speedrun level, and this level isn't super tight to the point everything has to be executed with perfection (although it still requires some obstacles to be one-cycled). I needed to figure out a few things, like both setups involving Hammer Bros, but it was much easier than the previous level, and most tricks are things we've already seen in the hack. It's not a level that stands out a lot, but i appreciate the idea it had.
The hardest trick for me was actually the sequence of jumps right at the start. I don't think this is a difficulty spike though, and i found a way to make it 100% consistent.

Special Stage 3: The hardest level in the hack, in my opinion. This level is all about the Fishing Boo, which is both neat and terrifying! While River Dyx and Aneha's House both had the presence of a Fishing Boo, it was usually sparse and could be dealt with by just brute forcing through. Here, however, is when we need to learn how to deal with him, there's no other way around it. Between using the Fishing Boo as a spin jump ride, having to avoid his flames in many instances and controlling his position, this level requires a lot of knowledge about him. And not only that, the level also starts with a full length jump that is one of the tightest in the hack. While i found ways to help timing this jump, i didn't find any way to make it consistent, and even after i beat the level, this jump is still where i died the most.
Leaving the difficulty aside, i can say this level does some neat things. I love the setup about getting the Boo Blocks out of the way, and all the Fishing Boo dodging and riding can be fun when you start learning it and pull off some sick dodges haha. With the Fishing Boo being the main gimmick of the level, it means each playthrough can vary a lot, learning how to adapt is important, and that by itself is neat, although frustrating at times.

Last Special Stage: And then we have the final level, and what we have is a level that, more than once, subverted my expectations, for better and for worse.
The beginning is intimidating. Having to jump into a Hammer Bro platform and then avoid two smashing spikes seemed scary lol. But despite that, i learned how to overcome it very quickly, and what followed was a level that got steadily easier up until the midway point. There was one tight 1 tile jump with a spike ceiling, but aside from that, the platform riding section and subsequent smashing obstacles are very easy.
Past the midway, it's just one jump that leads to the boss door, and the "bossfight" itself. The bossfight itself was difficult, but mostly because it's a cycle-waiting hell. Between a Disco Shell, a Bowser Statue, a Podoboo and layer 2 scrolling, we have to wait for an opportunity for all of them to line up to be able to proceed. That was not a fun obstacle to play, but most of it is learning the timing for when they line up. I did pause to manipulate the Bowser Statue as well.
But the real deal here was actually the room before the boss. It's just one single jump, but that single jump holds the absolute worst kaizo block in this entire hack! It needs to be a full length jump, so there's no way for you to actively avoid the kaizo block, the only way to avoid it is jumping at the right spot. Jump too early and you can't make the jump, jump too late and you hit the kaizo. I'm not exactly sure, but i think the window for getting this jump is something like 1-3 pixels. That was one of the most dreadful single tricks in this hack, on par with Cerulean Cave's last jumps and Special Stage 3's first jump.