That's alright. Thanks just the same. I was thinking about actual retro platforms instead of simulated feel. For example PCM wouldn't be useful for SNES/N64/CD-less Genesis and DOS. And for the CD systems, the need to keep constant audio feed going, would impose restrictions. For instance PSX 2MB RAM/1MB VRAM configuration, with the loss of ability to cache in additional data on demand, would mean quite limited and bland levels. DOS CD game would be fine, since you can install it and leave CD just for the music. People used to provide .mid files even though they didn't sound like final song, when MIDI had a comeback in Japan around 2010 in RPG Maker circles. Not that common anymore, I understand.