I got the menu system working (finally). Turns out I forgot to declare all the other buttons. 

Brain not working.

I got the weapons mostly moving, though the direction is solely built on a handler.
For most of them I'm only using an 'area2d' which doesn't use the physics process. And I miss that already.

Next update, hopefully I can get the players and enemies to deal damage to each other and then some kind of AI.