Kill as many waves of enemies as you can, with friends online or take fight alone.
This mod is fun and all, but can get quite boring. I think it needs a new overhaul on the defense mechanism, perhaps give us a choice of adding more mercs next to us on the battlefield. That, or add some prop that is actually worth having for defense.
What it really needs?
(With what I stated above) Maybe an addition to the props, we can buy a turret system?
That's all for now. A little tidying it up here and there and I think this mod will get the attention it deserves.