Think of Warband, or Dwarf Fortress. Those games are designed for player made modifications, so there are nearly unlimited ways to play those games. There are star wars mods, eauestria mods, colonial period mods, skyrim mods, steampunk mods, modern mods, lotr mods, fallout mods, zombie mods, etc etc etc...
Now imagine if LiF:YO was fully modable.