Suggestions

[Superjustinbros]

I say we should keep them, but only the -1 and -3 of the Japanese version since they look unique enough and they're far easier to reach than other "Minus/Glitch Worlds" which require hacking or other forms of manipulating the cartridge/rom- you only have to do the Minus World trick on the Famicom Disk System version to get these two particular levels.

Not to mention they start to get pretty uninteresting and repetitive the further in you explore, like "Here's a Coin Heaven or 6-3 but it's underwater" or "Here's a castle level but it's underground and filled with brick blocks instead of castle wall tiles and has weird geometry".

If anything you're better off compiling the more unique and interesting ones into a .zip so they don't clutter the main section.