I like the creative way of the game. As I understood you have little knowledge on how to work with Godot, so you came up with solution with your limitations, and it's great! You could change Godot Icon with pixeled cube with two black dots and get your character!
Then you could add randomly spawned white dots or apple icons to feed your same size characters, so it would unique behaviour.
Only thing that would be better at this stage is movement with the mouse instead of just WASD.