A little too challenging when the enemies are underneath you, and the shooting sprite/animation is fairly overwhelming and seizure-y to me, but other than that it seems to work the way you intended.
The game might be too unforgiving right now because of how random the enemy spawns are. I'm going to try and implement aiming with the mouse, so we'll see if that makes the game less unfair.
As for the seizury shooting animation, I'm pretty sure I can fix that by reducing the fire rate.
Thanks for your feedback!