@robusco said in Multiplayer online and homebrews:
In order to do what interests to me, is the PI 3B also a good model?
Yes, but you might consider the 3B+ model released last year. The Pi4 is also out, but it's not fully supported by RetroPie yet.
Is there a list of which games of which systems can be played online?
It depends on the emulator used. The lr-.. emulators - Libretro Cores - that run through RetroArch can have Netplay ability - see https://retropie.org.uk/docs/Netplay/. You can consult the core page at https://docs.libretro.com and see if it has Netplay enabled (see for instance http://docs.libretro.com/library/mame2003_plus/).
The other thing I was asking about Homebrews is:
Wich version of Streets Of Rage Remake and Open BOR runs fine and have the almost game compatibility? I have to use two version of Open BOR to make the old and newest game both running?
I don't know about SORR and OpenBOR compatibility. In RetroPie, OpenBOR uses an old fork which is optimized for the Pi, could be it's not compatible with games created for recent OpenBOR games - there's whole topic for this with lots of details here.