The main level uploader is now working as well as intended, and the downloader, too is functioning the way it oughta.

Next I need to make the web-based uploader work just as neatly.

-=-=-

At the moment, it simply uploads the file but then only takes the first level pack from the upload. I instead need to make it analyse the entire file, taking any complete level packs and adding them into the online level collection.
Once done, the script simply exports ALL the current online levels into a big .lev file which can be plonked into the filesystem of your 3DS.

It shouldn't be too hard to figure out the methods for that, since the level files have been specifically made in chunks of 4096 bytes.

Once that's up and running, I *think* that the only important piece left to work on is the last few levels of the main game. I've got about 16 more levels left to build, and am going to attempt to make them all nice and big.
I could still do with adding in some new tiles, but .. *shrugs*