Super Mario World (SMW) is one of my favourite games, so much so that I have dedicated a lot of time learning the craft of ROM hacking, which is the practice of making modifications to your own copy of the game to make a game of your own.
Crime!
Not at all, ROM hacking in this context refers to the process of modifying the contents of your copy of Super Mario World (that you legally obtained) as to change aspects of the game as you wish; downloading or distributing copies of the resulting ROM or the original Super Mario world ROM is when it gets legally questionable as that would contain Nintendo's intellectual property.
Hobbyists like myself, who are making and playing romhacks are simply distributing patch files which are all new material—made from a delta between the a modified ROM and the original game—that you apply to your copy of the original game to modify it prior to playing, so at no point is the distribution of copyrighted material taking place.
How I Got Here
I don't have a deep history in ROM hacking or Super Mario World, or any Mario games for that matter as I wasn't a Nintendo household growing up, but I had bought Super Mario Maker 2 on a whim when it came out and enjoyed noodling around in the level editor there. SMM2 led me to the community of level makers and content creators online who eventually exposed me to Kaizo and Super Mario World ROM hacks. The rest is history.
ROM Hacking became a critical hobby for me at a time when I was getting burned out creatively by my job as well as the onset of the COVID pandemic. Working on hack projects was a place could put creative energy that was just for me, and in a completely different and rewarding way from my work, and becoming involved in the hacking community has led to me getting to know many great people for which I'll value for many years.
Things I've Made
I have made a number of hacks over the years as well as contributed to collaboration projects or made levels for events. You can find a not-up-to-date breakdown of those on the following page.
How to Start Hacking SMW
With your copy of Super Mario World, you can get started with hacking today using a variety of freely available tools, the most notable and essential of which is the level editor: Lunar Magic, by FuSoYa.
Image courtesy of FuSoYa
Lunar Magic is full of features that allow you to greatly modify any or all the levels of Super Mario World or make new ones, as well as modify the underlying function properties of the game by modifying the assembly language that the game is written in.
A more advanced technique of ROM hacking involves writing and inserting new code that significantly modifies the game, such as adding new enemies, changing the physics, adding quality of life, custom graphics etc. all of which are done with tools used in addition to Lunar Magic.
Getting Help
Super Mario World ROM hacking has been around virtually since the game came out and people have been making hacks, tools, modifications, new code, new graphics, and patches for the original game for years. The largest hub for this is the site SMW Central that provides all sorts of help, tools, forums, and resources one needs to get started ROM hacking.