Unvanquished is an open-source FPS game featuring team-based strategy and RTS elements, pitting humans against aliens in a futuristic setting.
https://forums.unvanquished.net/
This likely isn't Debian-specific.
I don't know about the universal zip, but unvanquished-server works fine here. You'll find some config files are in /etc/unvanquished-server; server files are in /var/games/unvanquished-server/.unvanquished; .pk3s belong in /var/games/unvanquished/pkg. You'll need to set an rcon password and, if you're using IPv6, uncomment the line containing “net_enabled”.
It might also be worth checking permissions of the resources vs the user running the server.
Nah, I think it's my fault. I forgot to include the exe and .so files. You can fix it by setting vm.game.type to 0
+set vm.game.type 0
Result: