Tip: Switch palace switches normally disappear if you replay the level. However, if you insert them as direct Map16 and use the hex-edit at $00EEB2 in the ROM map, you can replay the level without a problem.
Man I had no idea complex music like this was possible to port into SMW. This is too good! I had to compare it to the original version, and it seems like some echo effects and background synths are notably missing, but it's impressive how close this is to the original. I'm guessing the samples were recreated from scratch? The percussion samples sound a little different, but the lead synth sounds ripped from the original song.