Very cool game! I just beat it!
The music was really good and the enemies challenging, the sword ones they forced me to change playstyle (I couldn't circle around them and attack like I did with the red and green ones and the boss. The purple ones really destroyed me 3 or 4 times in a row.
However, I would suggest to make the Mouse-pointer-godot less opaque, I couldn't keep it directly on enemies because if I did so I wouldn't be able to see them. Also some arrows that point at enemy off-screen? I didn't know how many enemies would come, what type, or even the direction!