I did it different way. You don't even have to move left when touching the note block. You can screen scroll instead. Note it's possible in pre-patched hacks only, like maybe the base KLDC2017 ROMKLDC 2020 progress: 50%
I knew about this for a rather long time as well - but I didn't find it on the list, which is why I posted it here.
Another glitch I haven't found on the list: If you jump on the first frame after you come out of an upwards pipe exit, you won't trigger any effects of the block you just jumped off (you won't be hurt by Munchers, the creating/eating block won't be activated if it is a brown block etc.)
For some reason when I use shell DF and koopa claim in it, after stomping on para-koopa, koopa gets stunned, just like shell-less koopa (I can kick it), as seen here. Also, I somehow broke P-switch music with pause. (Loops infinitely)
Yeah, those are all in the original game. Nintendo does that to prevent vertically-moving sprites (like the magic or bullet bills from the surrounded generator) from being spawned forever, and to prevent the Spike Tops from walking around the underside of the ground. But it's definitely meant to be the bottom of the *level* and not just the screen, which is what that patch accomplishes. Professional frame-by-frame time wizard. YouTube - Twitter - SMW Glitch List - SMW Randomizer