The recommended emulator for this hack is Snes9x 1.60, with the option Separate Echo Buffer from RAM enabled (in Emulation -> Hacks). The hack works on bsnes but a loud noise can be heard at the start of the musics.
If you really want to use ZSNES 1.51, you may need to change the "per2exec=100" to "per2exec=150" in zsnes.cfg to remove some of the slowdowns.
Hack thread (you can reply on this one):
- Fixed music in world 4 and special world that broke on accurate emulators
- Fixed a few typos
- Disabled L/R scroll in Kinder Surprise to remove a game freeze
btw I made this update to fix some crashes on accurate emulators.
Everything else is the same as it was originally made 11 years ago (minus some typos I decided to fix because my english really was bad).