@OP Don't take this as complaining because I can't argue with free.

However here's my opinion. You should focus on fixing bugs instead of implementing new devices into the emulator.

Emulating still isn't perfect on PC even for NES and optimising code for all these different devices is probably impossible to do by yourself.

I tried the emu and NES games ran too fast, sound(i.e. music) skipped while SNES games didn't even have working sound. (tested 5 games)

Another feature you should consider adding is the ability to hold down two buttons at a time(i.e. in Megaman X you sometimes have to keep the shot charged and be able to jump at the same time). Although there might be a chance that you could actually pull this off already, but it's really hard to do then because I didn't manage.