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.
This patch allows you to have multiple death songs using various logics: per-level, per-world, randomised, per-player... or even all of them ! (in this order of priority)
See .asm file for more details.
Important note: AMK users, be wary of the original songs order change. In addition, to ensure your custom music causes no pause, be sure to insert at as a global song.