This is a simple space invaders clone which is multiplayer made with Love2D and the sock.lua library.
If you are hosting, download Space.Defenders.Server.zip
from the releases and run it.
Players will need to put in your IP address in order to join.
I don't know which IP address because I don't know much about networking, and I think you'll also have to port forward or something.
If you don't wanna do that, then you can connect to Hamachi and players can join through that.