So, I've created a thing. Being inspired by SMW Kaizo hacks, I decided to make my own level, using the latest build of SMBX2. It should be beatable in theory, but because of my lack of skills and because of my computer acting strangely recently, I can't say for sure. It's the first time I actually posted the level on this forum, so please let me know if something's wrong.
UPD: Link updated, made a couple of fixes.