Nice work! A very aesthetically pleasing game.
Like others have mentioned, I think the movement needs some work, and I think I know the problem.
I would bet that you have an input method that is doing something like:
if event.is_action_pressed("move_right"):
move_right()
if event.is_action_pressed("move_up"):
move_up()
etc.
(not sure if that formatted properly)
Instead, what you should do is create a vector, using var vector = event.get_vector("up", "down", "left", "right") which is a new feature in Godot 3.4, and that will basically give you a (non-normalised) vector with both axes between -1 and 1, and then you can just use that vector in your movement script instead.
Hope that helps! I learned this strategy in the jam as well to control the barracuda.