I added VGM support to the SoundTrax music webapp! Editing VGMs isn't easy because of the nature of the format.
Some data is lost during import, but if you want to rework a classic, this is your best option I think!
AY8910 and SN76489 chip support is good, covering most 8-bit music. Capcom QSound, Neo Geo YM2610, Sega YM2151 and Data East YM2612 is possible but results vary. Nintendo Gameboy, NES & Sega Master System are fairly good. Work for these other systems is ongoing...
SoundTrax works in a web browser, so there's zero install and maximum portability.
There are live demos for tracker beginners: you can learn by example as SoundTrax takes over your mouse and shows you the way.
VGM, MID & MOD import. Gamepad and MIDI keyboard hardware support. Export as Opus audio files. Feedback forum.
Embed songs & sound effects in any website with the tiny playroutine library.
https://st.1up.org
Enjoy!