People have been hacking the original "Super Mario World" and "Super Mario Bros. 3" for years, twisting them from family-friendly games into a matrix of malicious, writhing vipers that takes you to a world of nightmares and pain.
And the community loves it.
The release of "Super Mario Maker" has broadened the community and its staleness has led up to further discovery of the joys of Mario romhacks. The game has inspired others to study the ways of Lunar Magic (the tool used to hack SMW ROM), creating a wide range of excellent content creators.
Among these creators is Twitch streamer, BarbarousKing (Barb), whose "Kamikaze Bros 3" and "Grand Poo World" are now hallmarks in the community's hall of fame.
Barb has released "Grand Poo World II" a couple of weeks ago. And just as he promised, this sequel focuses more on tight platforming than kaizo tricks such as shell jumps. Oh, shell jumps exist, but so far that's the most advanced tech you'll need to plow through this game.
It kicks off real smooth with precise jumps and high-octane platforming. Even if you've never been much of a kaizo player, yes, you will eventually get through this. But as the game progress, things become clear that you will need more than skills to get through this gauntlet of pain.
Barb ensures each level is unique in its own way, introducing new mechanics. The boss fights are unique and amazing. Even horrible water levels are great here. (For context, no one likes water levels. No one.)
Until some time ago, most boss fights in Mario romhacks are rebuilt Reznor fights, or Wendy, or a King Boo. Because, according to some people I've talked to, these fights require little to no coding. Making bosses would require serious coding skills. And this is a testament to the hours Barb put into making this romhack as best as he could make it. This doesn't include the hours spent by other streamers, contributing to the game, playtesting it, lending their coding experience, and composing original music (shout out to com_poser).
Barb is careful to lay a ton of easter eggs here and there, showing us portraits of other Mario streamers such as TheBeast, Juzcook, and a few others that escapes my mind. (Ryukahr and Carlsagan42 are probably there, they should.)
In all, "Grand Poo World II" is a massive achievement for Mario players and in the romhacking community. It's a definite must-explore world.
If you want to get started with the basics of Lunar Magic. You can tune in to Barb's YouTube channel.