Preload all resources

When instantiating a scene (like a weapon, and enemy, anything) never load and instantiate, instead preload anything in an autoload class then use it when needed.

As an example, fo fire a bullet add an autoload script called res.gd (class Res) with content like this:

var shuriken := preload(\"res://bullets/shuriken.tscn\")
var red_apple := preload(\"res://items/red_apple.tscn\") # preload all the ones you need
...

Then in the shooting script add this function:

func add_bullet(weapon_name, pos):
    var bullet: Node = Res[weapon_name].instantiate()
    bullet.position = pos
    get_tree().root.add_child(bullet)

Spawn the bullet in this way:

add_bullet(\"shuriken\", player.position)