Really nice. You did a very nice job on scoping your game: it absolutely does not look half-finished. Smooth CPU movements, nice and simple graphics that fits perfectly the theme. Honestly, if you had 10 hours to make the game, I'd say you should do the exactly same thing and just watch some movies on the other 7 hours.
How's the CPU AI? Does it check for the closest ball and track it's movement? It seemed unbeatable at first, but then I was actually able to win when the pink ball was super slow but also very close to it, and I threw the blue ball on the other side!
You mentioned Godot physics, is everything there done with the default Godot physics? Or did you implement any custom physics yourself?