A few weeks ago, BarbarousKing released Grand Poo World 2, for which some people took off work to play and enough viewers watched for it to peak at #18th most watched on Twitch. The thing is, Grand Poo World 2 isn’t a standalone game - it’s a romhack of Super Mario World.
The world of Super Mario World (or SMW) romhacking is historied and diverse. Using programs to add custom enemies and music, and a program to edit the levels in the game, enthusiasts have made custom edits of SMW since 2000. Released as patches online, these hacks range in style from puzzles, boss rushes, and of course, Kaizo.
The term “Kaizo” is a Japanese word loosely translated as “remodeled,” though it’s used as a descriptor of difficulty. Kaizo Mario is the name of one of the earliest popular romhacks. It became notable for its design that focuses on trial-by-error traps and tight movements, all more demanding than the original Mario World. Over time Kaizo became a sort of supergenre that encompassed other branching styles, though the focus on tight difficulty remains the centerpiece.
Grand Poo World 2 is one such Kaizo romhack. There are precise jumps, tight item throws, and plenty of traps (or “trolls” as the community calls them). Watching someone like Grand Poo Bear, whom the hack is named after, play through the game might not get across the appeal. It can take hours to clear a single level, let alone some of the harder challenges. Understanding the design of the romhack requires understanding this appeal.
At the core, Kaizo romhacks follow a few specific tenets or commandments. These are:
A harder difficulty means completing a level is more rewarding
It should look just barely possible, not impossible
Traps/trolls should be used sparingly and wisely - they act like slapstick gags, not exactly challenges
Diverse levels lead to a spread-out experience
I’ll go through what I mean in order.
The first point is sort of why people enjoy these games, as well as many other games with high difficulty. The number of deaths or losses is outweighed by the sense of relief and accomplishment by beating the level or section. Playing these games and romhacks is a test to your own abilities, and proving to yourself you can do it is another source of accomplishment. This leads in to the second tenet. For players to want to beat a level, the level has to look and feel possible. Most tricky jumps and segments in Grand Poo World 2 are designed so if you fail, you only fail by a small margin. Often the thought of “I just need to be a little faster” outweighs the negatives of dying to a jump - the salvation being in sight makes victory tangible.
That being said, one of the genre staples is unforseen traps. In Kaizo Mario, oftentimes the designer would place invisible coin blocks - which only reveal when struck by Mario - in the path of players’ jumps. These were mostly placed where the player would naturally jump, forcing the player to rethink their approach and keeping them from playing on autopilot. Most modern Kaizo romhacks limit the number of trolls used. While some romhacks are based around a substantial amount of trolls, a romhack like Grand Poo World 2 which is centered mostly on platforming keeps them in a few key places. This coincides with the growth in Twitch streamers playing romhacks - well-timed trolls can accentuate a viewing experience as a sort of gag, like a pratfall. Often these tricks are easy to recognize once you’ve fallen victim, so it’s less likely they’ll stop progress more than once or twice.
Finally, most Kaizo romhacks rely on diverse challenges without repetition. SMW originally was designed so each level had a central focus, whether an enemy or platforming variation. Kaizo romhacks, and many romhacks in general, preserve this by giving each level a theme or concept. They then tie the challenges back into that theme. In Grand Poo World 2, the 3rd level, Riptide, is focused on gaining speed early and keeping it by not touching a directional button. The first half uses sloped platforms to do so, and the second uses quickly-flowing water. Setting themes for each level keeps levels from feeling scattered or lengthy. Importantly, using each challenge once keeps the difficulty high and the player constantly invested. A puzzle game wouldn’t repeat puzzle ideas, or else the player would solve them without thinking. Kaizo romhacks are the same way.
(Screenshot of Riptide, the 3rd level of Grand Poo World 2)
All this said, oftentimes the driving factor behind these romhacks is just finding what’s cool or what’s interesting. It can be enough of a guidepost to uncover a weird mechanic or interaction in the game and see what you can create from it. In a way, much of good game design starts with an idea and branching outward, but never disconnecting from that center. The niche-within-a-niche of SMW romhacks is founded on those same principals, and GPW2 is the prime example.