basically the reason why is so the levels can be split into different folders with everything working as intended (this would also allow for the script for each world since each world will have items you need to collect to simply be default.nut with it working in all levels in that world), things would be able to be done more easily and i would be able to add new enemies by modifying old ones

i would also be able to stuff like new sounds, be able to fully replace coins and stuff like that (brick blocks dont have a way to change the sprite of coins)

the negative stuff about this would be that it would be hard to add bug fixes / new features from future supertux versions and it'd require more disk space as it would be an entire supertux mod (although i'd try to cut out a lot of the original supertux stuff that wouldn't be needed in the mod)

also it would lose compatibility with add-ons made for supertux

i kind of wish supertux had more modding support like a certain haxeflixel game i used to play and mod a lot, like being able to add things into the data folder and have it work in add-ons (if that doesn't already exist?) and creating custom enemies (possibly using more scripting stuff or even better, a custom enemy object? would be very difficult to add probably since there would need to be a way to not crash the game when certain enemy behaviors are combined so i understand why supertux team wouldn't wanna add this)

to get the best of both worlds, i'd try make an add-on version, but if i do make any custom enemies, levels would have to be recreated.

making this be a mod or an add-on would not be able to happen right now, but i might still put a poll on here and youtube asking for what everyone thinks of this being a mod or an add-on.

also another postive thing about this being a mod would be changing the logo, name and icon. but that really doesn't matter i think.