I thought you could add another game mode. For example, an arena mode where one after another more and more COG’s appear and supply you with materials that you can use to make better weapons and build gun towers to support you. You can also get better armor and healing.
IT also can bee added for the incoming Multiplayer.
Adding a gamemode isnt just as easy as clicking a button though. Making a full tower defence out of it will deffinetly take up a lot of rescources most would want spent on the main game.
Also you should work on your titles
While it sounds somewhat cool, I can’t imagine it coming to the vanilla game.
could be a mod