Sharing the Levelset
Now that you have created your levelset, you probably would like to share it! Luckily, this is easy to do with ReTux.
ReTux levelset files are distributed in standard Zip files with the custom .rtz extension. To create one, simply pack all the files into a Zip file, with directories based on the "data" directory in your ReTux installation, preserving paths. For example, if your levelset file is "foo.json" and your level file is "bar.json", the Zip file would have the "levelsets" and "levels" directories in its root; "levels" would contain "bar.json", and "levelsets" would contain "foo.json". Any other dependencies (such as extra music) would be included in the same fashion. This isn't exactly what happens, but think of the zip as being extracted by the end-user directly into their "data" directory.
Once all necessary files are in your Zip file, simply change the file's extension to ".rtz" and give the file to someone else! That person will then use the "Import levelset" entry in the Options menu to automatically import the levelset.