I have a minor nitpick, however. Instrument @30 is defined in instruments, yet always called with $ED. It's more efficient to just bake the ADSR directly into the #instruments definition so you don't have to do @30 $ED $XX $XX each time. Also, be careful with $EE on SFX channels, since it detunes sound effects.
That aside, this is a really nice port! I love it.