Jemu

Are you trying to do local machines or through the internet using private LAN? you'll need to change the adapter network to your private LAN IP and adapter subnet to 255.255.255.0 in your emu config if you're doing that. If you're doing local machines then it should just work out of the box. All players need to be on the same version and same spec (valk vs non) edit: also everyone should have their asphyxia on as well

Not sure if this needs to be said, but local matching through virtual LAN is working flawlessly! Also, you can use the program Fullscreenizer and run it as admin, then have the game in windowed mode thru spicecfg and itll be borderless fullscreen. Also skips the refresh rate check of your monitors if you select windowed afaik