func _process(delta)

 I wish that GodotScript was just Python. It isn't, for a reason, but I don't know the reason yet. It could be:

1. GodotScript came first, or before Python was widely known.
2. Python is too hard to integrate. In this case, they considered *creating an entire new language interpreter* easier than incorporating Python
3. True Python implies that the entire marketplace of Python libraries can be used, and that may have been too difficult to achieve.
4. Python doesn't match the authors' internal model for how to do scripting
5. Godot was started as a personal project, and a scripting engine was one of the "fun" things that they wanted to do with it.

In any case, I have reached the part of the tutorial where scripting is introduced. The template for a script for a node includes the following interesting code:

extends Node2D

# Called when the node enters the scene tree for the first time.

func _ready():

pass # Replace with function body.

# Called every frame. 'delta' is the elapsed time since the previous frame.

func _process(delta):

pass

The interesting one is _process(). I can imagine a mode of using the game engine where I just use it as a graphics engine -- every frame, this function is executed by the graphics engine, where it does all of my custom physics etc, changes the position properties of a bunch of nodes, then returns and lets the graphics part of the engine do its thing. 

Seriously, this function can implement a Runge-Kutta numerical integrator from the ground up -- it could use the node properties as part of its state, can keep global or static variables for the rest, and implement any law of motion I can think of. I'm not smarter than Newton or Euler and I intend to use their laws, but I don't *have* to.

If this was all Godot did for me, it might be just right. I'm still exploring, seeing what else it can do for me (I'm on part 25 of 47 of the Intro to Godot course). I strongly suspect that the engine does have a physics component though, since I have seen "gravity" as a property of some of the nodes.