The game crashed right on the main menu for me after some time (due to the issue in the rocket bullet script), and if I started the game quickly enough to prevent that, it would crash due to the `Global.Base` being an invalid instance.
Godot has this tricky behavior where a node freed with `queue_free()` does not assign its previous references to `null`, but to something called a "previously freed instance". That doesn't evaluate as `false` when you do `if target:`, and thus it would then try to call methods on the previously freed instance, triggering errors (in debug mode) or crashes (in release mode).
I suggest you give it a run with Godot 3.2.4 beta 3 which does a better job at reporting these issues than 3.2.3 stable.