Big fan of turn-based gameplay here so I love the idea. I did notice a bit of a double-tapping issue where sometimes I'll shoot a few squares to the right when I do a single move input.
I experienced it too, but I have no idea where it comes from since Godot has a "just pressed" feature that is supposed to prevent repeat inputs. This might be caused by some sort of lag or a faulty/old keyboard (which would not surprise me in my case).