Old super mario bros ad look at dem graphics
Then came implementing an "Add Object" GUI, without which editing Mario Levels would become an exercise in extreme tediousness. I implemented the drag/drop support I had originally planned for SMRPG's editor, and rewrote the GFX routines to handle Mario World's format. Then I reused the old GUI for the unfinished prototype of the Sailor Moon Map Editor to begin constructing the level editor. I went on to decode the level layout data, which required disassembling a fair portion of the ROM's ASM code. I started out in February 2000 by figuring out the compression format for the graphics and building the necessary decompression and recompression tools.
I began looking into making an editor for SMW shortly after releasing the SoM VWF patch, mostly on a whim to see how hard it would be. It wasn't originally intended to be a long term project, but things turned out otherwise.
During its 19 year span of being the only level editor available for this classic game, it's inspired the creation of countless modifications of SMW by fans and casual players alike. Lunar Magic is a level editor I created for Super Mario World (SNES). FuSoYa's Niche - Lunar Magic SMW Editor Introduction