There was a sound expansion for the Master System, which gave it sound capabilities that are better than what Famicom had.
Makes sense if you won't add support for it in your homebrew, as it was never released outside Japan.
I think a Master System version with these improvements would be awesome.
Someone made a Wolfenstein 3D clone for Master System, using its hardware advantages for smooth graphics.
https://www.smspower.org/forums/19054-Maze3d
So it actually is possible to make Doom on NES.
It's incredibly impressive!
I've seen other attempts at 3d fps games on a variety of 8-bit systems, but none of them even attempted elevated floors.
The graphics could probably be improved by making it less blocky, but it would take a huge drop in framerate, because of the processing power needed to generate new tiles on the fly.
Anyways, it's an amazing tech demo.
I was gonna make the collision system in my game work by detecting the tile graphics themselves and their positions. (for example, a dude moves if there is 8 pixels of space next to him, and can't move any further if there is a brick tile right next to him without any space inbetween)
I would need to see some code example to know how to make it.