Hi man i really liked your game and played for quite some time.
A bunch of possible improvements:
I felt that the game was a bit to easy. one way to increase the difficulty would be to no longer enable the arrow spam, add a short delay between each arrow or increase the amount of enemys after some time.
Another thing that i would recommend you to change would be the music. I actually dont want you to change the music or sound effects, i thought that they were quite fitting but i would change the node that plays the audio atleast for the music. If you are using the AudioStreamPlayer2D node in godot the sound will be directional. This can be quit unpleasant if you use a headset. For me the intro sound was only on my left side. Just change the node type to AudioStreamPlayer instead and that should fix it.
All in all i really enjoyed your game.