What Exactly Is A “Kaizo” ROM Hack?


If you’ve ever stumbled onto a Kaizo video on YouTube, you will see some of the most frustrating and difficult looking Mario levels ever created. The difficulty, as well as the precision needed to complete even just one of these levels, is a sure sign that those that develop Kaizo levels are evil beyond reproach.

There is an interesting history behind Kaizo ROM hacks, and both the creation and playthroughs of Kaizo ROMs have carved out their own space in the hardcore gaming sphere.

What Is A Kaizo ROM Hack?

Kaizo ROM Hacks are generally associated with Mario games; Kaizo is considered a genre of difficulty that pushes players to their limits with extremely difficult level design. Every level of a Kaizo ROM will feature several frame-perfect sequences, as well as a plethora of evil tricks that can only be beaten through trial-and-error.

The balance to creating a good Kaizo ROM is level design that pushes players to their absolute limits while still being possible to complete through human error; Kaizo ROMs shouldn’t require the use of TAS to complete.

Part of the appeal (and the struggle) with Kaizo isn’t just the high-level of skill needed; it always requires patience. Levels will constantly have hidden blocks that send you to your death, fast auto-scrollers that will cause you to lose over and over, and there’s even some gimmicks where you can die after reaching the goal post, making you start all over again. The common nickname for Kaizo ROMs, “Asshole Mario,” comes from the obnoxious difficulty and constant trial-and-error.

How Did Kaizo ROMs Start?

The first Kaizo ROM was Kaizo Mario World in 2007 by T. Takemoto. It was a ROM hack of Super Mario World, which still remains the most popular form of Kaizo level design. 

This Kaizo received millions of views online when it was uploaded to YouTube, and helped spawn the Kaizo genre of Mario. T. Takemoto has uploaded two more Kaizo hacks, with Kaizo Mario World 3 being the hardest Kaizo hack that a human can beat.

The Kaizo hacks became extremely popular, not only due to players who showcased their skill by beating the hacks, but by streamers and content creators reacting (quite appropriately) with hilarious rage at the game’s frustrating difficulty. 

Because of the popularity of the Kaizo genre, several other games had Kaizo ROMs made with their engine, including Super Mario Bros. 3, Super Mario 64, as well as countless Kaizo-inspired levels in Super Mario Maker.

What Does Kaizo Mean?

“Kaizo” in Japanese means “reorganize” or “reconstruct” and as such, it’s a term that has historically been used in the ROM hacking community, since they are “reconstructing” these games. However, the popularity of Kaizo Mario World also means that Kaizo is used to incredibly frustrating and difficult level design.

Kaizo Runs Today

Today, there are many Kaizo-style runs across many ROM hacks, with SMW Central being a hub for the discussion and creation of these ROMs. Believe it or not, there is even a wide spectrum of difficulty levels amongst Kaizo hacks, with the two categories being Kaizo: Light and Kaizo: Hard.

Many offshoots of Kaizo Mario World, all with their own unique twists but still holding onto the high degree of difficulty, have become popular in the ROM hacking community. Some examples of these include Grand Poo World, Super Panga World and Super Ryu World 2.

Kaizo ROM hacks are a treat to watch, especially when a high-level player is clearing through them and making it look easy. However, if you choose to try and play a Kaizo hack, do so at your peril.