Netplay via RetroArch
Netplay with RetroArch is very simple. Since RetroArch is a frontend for multiple emulator cores, setting up netplay for any core is very simple (as long as it supports it!), and is the same procedure.
For Genesis, we are using the Genesis Plus GX core for netplay.
For SNES, we are using the Snes9x core for netplay.
For installing RetroArch , please check out this page on nhl94online.com - Getting Started
The advantages to using RetroArch for netpla